Instytut Podstawowych Problemów Techniki

Liu S., Wu J., He S., Yuan X., Stupkiewicz S., Wang Y., Effect of substrate stiffness on interfacial Schallamach wave of flexible film/substrate bilayer structure: Cohesive contact insight, TRIBOLOGY INTERNATIONAL, ISSN: 0301-679X, DOI: 10.1016/j.triboint.2024.110358, Vol.202, pp.110358-1-14, 2025

Abstract:
As the critical feature of the stick-slip for soft materials, the interfacial Schallamach waves of flexible composite structures are essential for smart tactile sensors to realize sliding perception. Herein, the Schallamach waves of polydimethylsiloxane film/substrate bilayer structures with three substrate stiffnesses regulated by porosities are investigated by setting up in-situ sliding tests and establishing finite element models with mixed-mode cohesive contact. Inhomogeneity in microcontact stiffness disrupts the continuity and synchronization of the Schallamach waves, resulting in non-periodic fluctuations in the contact force. The buckling phenomenon of the film structure marks the transition from stick to slip. This buckling induces a shift at the crack front from normal compressive stress to tensile stress, leading to mixed-mode damage.

Keywords:
Stick-slip,Polydimethylsiloxane film/substrate bilayer structures,Schallamach wave,In-situ sliding test,Mixed-mode cohesive contact model

Ustrzycka A., Dominguez-Gutierrez F.J., Chromiński W., Atomistic analysis of the mechanisms underlying irradiation-hardening in Fe–Ni–Cr alloys, International Journal of Plasticity, ISSN: 0749-6419, DOI: 10.1016/j.ijplas.2024.104118, Vol.182, pp.104118-25, 2024

Abstract:
This work presents a comprehensive examination of the physical mechanisms driving hardening in irradiated face-centered cubic FeNiCr alloys. The evolution of irradiation-induced defects during shear deformation is modeled by atomistic simulations through overlapping cascade simulations, where the nucleation and evolution of dislocation loops is validated by transmission electron microscopy images obtained from irradiated FeNiCr alloys using tandem accelerator. The effect of different shear rates on the microstructure of irradiated materials with a specific focus on the changes in the density of voids and dislocation loops induced by irradiation was analyzed. Additionally, the fundamental interaction processes between single irradiation-induced defects contributing to irradiation hardening, such as voids and dislocation loops in the alloy are explained. The analysis at atomic level indicates that both the dislocation loops and the voids exhibit strengthening effects. Furthermore, the nanometric voids are much stronger obstacles than dislocation loops of comparable size. The mechanism of cutting the voids leads to an increase of voids density and thus contributes to an increase in irradiation hardening. The mechanism of collapse of small voids into dislocation loops leads to decrease of voids density and at the same time increase of loops density. The coupling effect between the density of voids and dislocation loops is determined. Finally, the novel, physical mechanisms-based model of irradiation hardening and dislocation-radiation defect reaction kinetics are developed, which consider the mechanisms of void cutting, void shrink and void collapse to dislocation loop.

Keywords:
Radiation-induced defects,Irradiation hardening,Collision cascades,MD simulations,Radiation defects evolution,Cr-rich alloys

Lisowski P., Jóźwiak-Niedźwiedzka D., Osial M., Bochenek K., Denis P., Glinicki M. A., Power ultrasound-assisted enhancement of granulated blast furnace slag reactivity in cement paste, CEMENT AND CONCRETE COMPOSITES, ISSN: 0958-9465, DOI: 10.1016/j.cemconcomp.2024.105781, Vol.154, No.105781, pp.1-19, 2024

Abstract:
This paper introduces a first-time investigation into the impact of power ultrasound (PUS)-assisted preparation on the physicochemical and mechanical properties of cement-granulated blast furnace slag (GBFS) composite pastes. Pastes containing deposited GFBS with varying particle size fractions, partially replacing Portland cement, were prepared using PUS (ultrasonic horn tip, 20 kHz, 700 W) in pulse mode in a vertical jacketed glass sonoreactor with closed-circuit cooling. Cement paste incorporating 20 wt.% GBFS as mass substitution with varying particle size fractions was characterized by several physicochemical techniques at different curing ages. Exploring the cement and GBFS interaction induced by PUS, the compressive and flexural strength, the elastic modulus and indentation hardness, the heat of hardening, the mineral composition of hydration products, and the specific surface area BET were evaluated for a curing time of up to 28 days. The grain size distribution of GFBS and the reaction mixture's pH were measured. Both mechanical properties, heat of hydration and nanoporosity exhibited strong sensitivity to PUS treatment. Sonofragmentation of GBFS particles (especially the 125–250 μm fraction) increased with increasing sonication time, resulting in a relative increase of fraction <63 μm and a decrease of fraction >125 μm by 275 % and 60 %, respectively. Using the obtained SEM-EDS data, a simplified mechanism is proposed to explain the effects induced by PUS treatment.

Keywords:
Power ultrasound treatment, Portland cement, Granulated blast furnace slag, Early strength development, C-S-H/C-A-S-H, Seeding effect

Dobrzański J., Stupkiewicz S., Towards a sharper phase-field method: A hybrid diffuse–semisharp approach for microstructure evolution problems, COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING, ISSN: 0045-7825, DOI: 10.1016/j.cma.2024.116841, Vol.423, pp.116841-1-23, 2024

Abstract:
A new approach is developed for computational modelling of microstructure evolution problems. The approach combines the phase-field method with the recently-developed laminated element technique (LET) which is a simple and efficient method to model weak discontinuities using non-conforming finite-element meshes. The essence of LET is in treating the elements that are cut by an interface as simple laminates of the two phases, and this idea is here extended to propagating interfaces so that the volume fraction of the phases and the lamination orientation vary accordingly. In the proposed LET-PF approach, the phase-field variable (order parameter), which is governed by an evolution equation of the Ginzburg–Landau type, plays the role of a level-set function that implicitly defines the position of the (sharp) interface. The mechanical equilibrium subproblem is then solved using the semisharp LET technique. Performance of LET-PF is illustrated by numerical examples. In particular, it is shown that, for the problems studied, LET-PF exhibits higher accuracy than the conventional phase-field method so that, for instance, qualitatively correct results can be obtained using a significantly coarser mesh, and thus at a lower computational cost.

Keywords:
Microstructure evolution,Interfaces,Laminate,Phase-field method,Finite element method

Darban H., Elastostatics of nonuniform miniaturized beams: Explicit solutions through a nonlocal transfer matrix formulation, International Journal of Engineering Science, ISSN: 0020-7225, DOI: 10.1016/j.ijengsci.2024.104054, Vol.198, No.104054, pp.1-18, 2024

Abstract:
A mathematically well-posed nonlocal model is formulated based on the variational approach and the transfer matrix method to investigate the size-dependent elastostatics of nonuniform miniaturized beams. The beams are composed of an arbitrary number of sub-beams with diverse material and geometrical properties, as well as small-scale size dependency. The model adopts a stress-driven nonlocal approach, a well-established framework in the Engineering Science community. The curvature of a sub-beam is defined through an integral convolution, considering the bending moments across all cross-sections of the sub-beam and a kernel function. The governing equations are solved and the deflections are derived in terms of some constants. The formulation uses local and interfacial transfer matrices, incorporating continuity conditions at cross-sections where sub-beams are joined, to define relations between constants in the solution of a generic sub-beam and those of the first sub-beam at the left end. The boundary conditions are then imposed to derive an explicit, closed-form solution for the deflection. The solution significantly simplifies the study of nonuniform beams with multiple sub-beams. The predictions of the model for two limiting cases, namely local nonuniform and nonlocal uniform beams, are in excellent agreement with the available literature data. The flexural behavior of nonuniform miniaturized beams, composed of two to five different sub-beams and subjected to different boundary conditions, is studied. The results are presented and discussed, emphasizing the effects of the material properties, nonlocalities, and lengths of the sub-beams on the deflection. It is demonstrated that the flexural response of nonlocal nonuniform beams is more complex than local counterparts. Unlike the local beams, dividing a nonlocal uniform beam into multiple sub-beams and then reconnecting them changes the overall stiffness of the beam. The study highlights the potential to design nonuniform miniaturized beams with specific configurations to control their flexural response effectively.

Keywords:
Small-scale beam,Transfer matrix method,Multi-material,Size effect,MEMS,NEMS

Bieniek K., Majewski M., Hołobut P., Kowalczyk-Gajewska K., Anisotropic effect of regular particle distribution in elastic–plastic composites: The modified tangent cluster model and numerical homogenization, International Journal of Engineering Science, ISSN: 0020-7225, DOI: 10.1016/j.ijengsci.2024.104118, Vol.203, pp.104118-1-104118-27, 2024

Abstract:
Estimation of macroscopic properties of heterogeneous materials has always posed significant problems. Procedures based on numerical homogenization, although very flexible, consume a lot of time and computing power. Thus, many attempts have been made to develop analytical models that could provide robust and computationally efficient tools for this purpose. The goal of this paper is to develop a reliable analytical approach to finding the effective elastic–plastic response of metal matrix composites (MMC) and porous metals (PM) with a predefined particle or void distribution, as well as to examine the anisotropy induced by regular inhomogeneity arrangements. The proposed framework is based on the idea of Molinari & El Mouden (1996) to improve classical mean-field models of thermoelastic media by taking into account the interactions between each pair of inhomogeneities within the material volume, known as a cluster model. Both elastic and elasto-plastic regimes are examined. A new extension of the original formulation, aimed to account for the non-linear plastic regime, is performed with the use of the modified tangent linearization of the metal matrix constitutive law. The model uses the second stress moment to track the accumulated plastic strain in the matrix. In the examples, arrangements of spherical inhomogeneities in three Bravais lattices of cubic symmetry (Regular Cubic, Body-Centered Cubic and Face-Centered Cubic) are considered for two basic material scenarios: “hard-in-soft” (MMC) and “soft-in-hard” (PM). As a means of verification, the results of micromechanical mean-field modeling are compared with those of numerical homogenization performed using the Finite Element Method (FEM). In the elastic regime, a comparison is also made with several other micromechanical models dedicated to periodic composites. Within both regimes, the results obtained by the cluster model are qualitatively and quantitatively consistent with FEM calculations, especially for volume fractions of inclusions up to 40%.

Keywords:
Periodic composite , Micro-mechanics , Effective properties, Elasto-plasticity, Particle interactions

Faghidian S., Darban H., Non-standard interface conditions in flexure of mixture unified gradient Nanobeams, International Journal of Engineering Science, ISSN: 0020-7225, DOI: 10.1016/j.ijengsci.2024.104127, Vol.204, pp.1-19, 2024

Abstract:
Structural schemes of applicative interests in Engineering Science frequently encounter the intricate phenomenon of discontinuity. The present study intends to address the discontinuity in the flexure of elastic nanobeam by adopting an abstract variational scheme. The mixture unified gradient theory of elasticity is invoked to realize the size-effects at the ultra-small scale. The consistent form of the interface conditions, stemming from the established stationary variational principle, is meticulously set forth. The boundary-value problem of equilibrium is properly closed and the analytical solution of the transverse displacement field of the elastic nanobeam is addressed. As an alternative approach, the eigenfunction expansion method is also utilized to scrutinize the efficacy of the presented variational formulation in tackling the flexure of elastic nanobeams with discontinuity. The flexural characteristic of mixture unified gradient beams with diverse kinematic constraints is numerically illustrated and thoroughly discussed. The anticipated nanoscopic features of the characteristic length-scale parameters are confirmed. The demonstrated numerical results can advantageously serve as a benchmark for the analysis and design of pioneering ultra-sensitive nano-sensors. The established variationally consistent size-dependent framework paves the way ahead in nanomechanics and inspires further research contributing to fracture mechanics of ultra-small scale elastic beams.

Shen Z., Sosa R., Bordas S., Tkatchenko A., Lengiewicz J. A., Quantum-informed simulations for mechanics of materials: DFTB+MBD framework, International Journal of Engineering Science, ISSN: 0020-7225, DOI: 10.1016/j.ijengsci.2024.104126, Vol.204, No.104126, pp.1-18, 2024

Abstract:
The macroscopic behaviors of materials are determined by interactions that occur at multiple lengths and time scales. Depending on the application, describing, predicting, and understanding these behaviors may require models that rely on insights from atomic and electronic scales. In such cases, classical simplified approximations at those scales are insufficient, and quantum-based modeling is required. In this paper, we study how quantum effects can modify the mechanical properties of systems relevant to materials engineering. We base our study on a high-fidelity modeling framework that combines two computationally efficient models rooted in quantum first principles: Density Functional Tight Binding (DFTB) and many-body dispersion (MBD). The MBD model is applied to accurately describe non-covalent van der Waals interactions. Through various benchmark applications, we demonstrate the capabilities of this framework and the limitations of simplified modeling. We provide an open-source repository containing all codes, datasets, and examples presented in this work. This repository serves as a practical toolkit that we hope will support the development of future research in effective large-scale and multiscale modeling with quantum-mechanical fidelity.

Keywords:
DFT, DFTB, Energy range separation, Many-body dispersion, van der Waals interaction, Carbon nanotube, UHMWPE

Kalita D., Mulewska K., Jóźwik I., Zaborowska A., Gawęda M., Chromiński W., Bochenek K., Rogal Ł., Metastable β-Phase Ti–Nb Alloys Fabricated by Powder Metallurgy: Effect of Nb on Superelasticity and Deformation Behavior, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-023-07285-5, pp.1-17, 2024

Abstract:
This study investigates the effect of Nb concentration on the mechanical properties, superelasticity, as well as deformation behavior of metastable β-phase Ti–Nb alloys produced via powder metallurgy. The alloys were fabricated through mechanical alloying, followed by consolidation using hot pressing. The resulting microstructure comprises fine β-phase grains with TiC carbide precipitates at the grain boundaries. The study reveals non-linear variations in the values of yield strength for the manufactured materials, which were attributed to the occurrence of various deformation mechanisms activated during the loading. It was found that the mechanisms change with the increasing concentration of Nb in the manner: stress-induced martensitic transformation, twinning, slip. However, all these mechanisms were activated at a reduced concentration of Nb compared to the materials obtained by casting technology previously reported in the literature. This is most probably associated with the elevated oxygen content, which affects the stability of the parent β-phase. The study revealed that superelasticity in Ti–Nb-based alloys prepared using powder metallurgy may be achieved by reducing the content of β-stabilizing elements compared to alloys obtained by conventional technologies. In this study, the Ti–14Nb (at. pct) alloy exhibited the best superelasticity, whereas conventionally fabricated Ti–Nb alloys displayed superelasticity at an Nb concentration of approximately 26 at. pct. The developed material exhibited a non-conventional, one-stage yielding behavior, resulting in a superelastic response at significantly higher stresses compared to conventionally fabricated Ti–Nb alloys.

Golasiński K., Maj M., Tasaki W., Pieczyska E.A., Kim H., Full-Field Deformation Study of Ti–25Nb, Ti–25Nb–0.3O and Ti–25Nb–0.7O Shape Memory Alloys During Tension Using Digital Image Correlation, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-024-07414-8, pp.1-10, 2024

Abstract:
A Ti–25Nb shape memory alloy (SMA) exhibits shape memory effect associated with stress-induced martensitic transformation from β to α″ phase. Addition of oxygen stabilizes the β phase and changes stress–strain response. Oxygen-added Ti–25Nb SMAs show a more distinct superelastic behavior. In this work, digital image correlation (DIC) was applied to investigate for the first time full-field deformation of Ti–25Nb, Ti–25Nb–0.3O and Ti–25Nb–0.7O (at. pct) SMAs. The specimens were subjected to loading–unloading tensile tests to study local and global mechanical characteristics related to activity of particular deformation mechanisms of the SMAs. Strain and strain rate fields were quantitatively compared at selected stages of each SMA’s deformation. It was found that the Ti–25Nb SMA exhibits a macroscopically localized Lüders-type deformation associated with the stress-induced phase transformation, whereas Ti–25Nb–0.3O and Ti–25Nb–0.7O SMAs show more discrete types of deformation related to activity of interstitial oxygen atoms. As a consequence, at particular stages of deformation, local values of strain rate of Ti–25Nb SMA were significantly higher than those of average strain rate. The results obtained in this paper provide a better understanding of the deformation mechanism in the oxygen-added Ti–25Nb based SMAs.

Sequeira A., Węglewski W., Bochenek K., Hutsch T., Jain A., Weissgaerber T., Basista M.A., Thermal Conductivity of AlSi12/Al2O3-Graded Composites Consolidated by Hot Pressing and Spark Plasma Sintering: Experimental Evaluation and Numerical Modeling, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-024-07506-5, pp.1-18, 2024

Abstract:
Functionally graded metal matrix composites have attracted the attention of various industries as materials with tailorable properties due to spatially varying composition of constituents. This research work was inspired by an application, such as automotive brake disks, which requires advanced materials with improved wear resistance on the outer surface as combined with effective heat flux dissipation of the graded system. To this end, graded AlSi12/Al2O3 composites (FGMs) with a stepwise gradient in the volume fraction of alumina reinforcement were produced by hot pressing and spark plasma sintering techniques. The thermal conductivities of the individual composite layers and the FGMs were evaluated experimentally and simulated numerically using 3D finite element (FE) models based on micro-computed X-ray tomography (micro-XCT) images of actual AlSi12/Al2O3 microstructures. The numerical models incorporated the effects of porosity of the fabricated AlSi12/Al2O3 composites, thermal resistance, and imperfect interfaces between the AlSi12 matrix and the alumina particles. The obtained experimental data and the results of the numerical models are in good agreement, the relative error being in the range of 4 to 6 pct for different compositions and FGMstructure. The predictive capability of the proposed micro-XCT-based FE model suggests that this model can be applied to similar types of composites and different composition gradients.

Jarząbek D. M., Włoczewski M., Milczarek M., Jenczyk P., Takesue N., Golasiński K., Pieczyska E. A., Deformation Mechanisms of (100) and (110) Single-Crystal BCC Gum Metal Studied by Nanoindentation and Micropillar Compression, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-024-07605-3, pp.1-11, 2024

Abstract:
In this paper, small-scale testing techniques—nanoindentation and micropillar compression—were used to investigate the deformation mechanisms, size effects, and strain rate sensitivity of (100) and (110) single-crystal Gum Metal at the micro/nanoscale. It was observed that the (100) orientation exhibits a significant size effect, resulting in hardness values ranging from 1 to 5 GPa. Conversely, for the (110) orientation, this effect was weaker. Furthermore, the yield strength obtained from the micropillar compression tests was approximately 740 MPa for the (100) orientation and 650 MPa for the (110) orientation. The observed deformations were consistent with the established features of the deformation behavior of body-centered cubic (bcc) alloys: significant strain rate sensitivity with no depth dependence, pile-up patterns comparable to those reported in the literature, and shear along the {112}<111> slip directions. However, the investigated material also exhibited Gum Metal-like high ductility, a relatively low modulus of elasticity, and high yield strength, which distinguishes it from classic bcc alloys.

Kaszyca K., Marcin C., Bucholc B., Błyskun P., Nisar F., Rojek J., Zybała R., Using the Spark Plasma Sintering System for Fabrication of Advanced Semiconductor Materials, Materials, ISSN: 1996-1944, DOI: 10.3390/ma17061422, Vol.17, No.1422, pp.1-15, 2024

Abstract:
The interest in the Spark Plasma Sintering (SPS) technique has continuously increased over the last few years. This article shows the possibility of the development of an SPS device used for material processing and synthesis in both scientific and industrial applications and aims to present manufacturing methods and the versatility of an SPS device, presenting examples of processing Arc-Melted- (half-Heusler, cobalt triantimonide) and Self-propagating High-temperature Synthesis (SHS)-synthesized semiconductor (bismuth telluride) materials. The SPS system functionality development is presented, the purpose of which was to broaden the knowledge of the nature of SPS processes. This approach enabled the precise design of material sintering processes and also contributed to increasing the repeatability and accuracy of sintering conditions.

Keywords:
spark plasma sintering, arc melting, semiconductor materials, half-Heusler, bismuth telluride, cobalt triantimonide, SHS, SPS

Strojny-Nędza A., Pietrzak K. Z., Jóźwik I., Bucholc B., Wyszkowska E., Kurpaska Ł., Grabias A., Malinowska A., Chmielewski M., Effect of Nitrogen Atmosphere Annealing of Alloyed Powders on the Microstructure and Properties of ODS Ferritic Steels, Materials, ISSN: 1996-1944, DOI: 10.3390/ma17081743, Vol.17, No.8, pp.1-19, 2024

Abstract:
Oxide Dispersion Strengthened (ODS) ferritic steels are promising materials for the nuclear power sector. This paper presents the results of a study on the sintering process using the Spark Plasma Sintering (SPS) technique, focusing on ODS ferritic steel powders with different contents (0.3 and 0.6 vol.%) of Y2O3. The novelty lies in the analysis of the effect of pre-annealing treatment on powders previously prepared by mechanical alloying on the microstructure, mechanical, and thermal properties of the sinters. Using the SPS method, it was possible to obtain well-densified sinters with a relative density above 98%. Pre-annealing the powders resulted in an increase in the relative density of the sinters and a slight increase in their thermal conductivity. The use of low electron energies during SEM analysis allowed for a fairly good visualization of the reinforcing oxides uniformly dispersed in the matrix. Analysis of the Mössbauer spectroscopy results revealed that pre-annealing induces local atomic rearrangements within the solid solution. In addition, there was an additional spectral component, indicating the formation of a Cr-based paramagnetic phase. The ODS material with a higher Y2O3 content showed increased Vickers hardness values, as well as increased Young’s modulus and nanohardness, as determined by nanoindentation tests.

Keywords:
spark plasma sintering, ODS ferritic steel, mechanical alloying, Mössbauer spectroscopy, nanoindentation

Frydrych K., Tomczak M., Papanikolaou S., Crystal Plasticity Parameter Optimization in Cyclically Deformed Electrodeposited Copper—A Machine Learning Approach, Materials, ISSN: 1996-1944, DOI: 10.3390/ma17143397, Vol.17, No.14, pp.3397-1-3397-14, 2024

Abstract:
This paper describes an application of a machine learning approach for parameter optimization. The method is demonstrated for the elasto-viscoplastic model with both isotropic and kinematic hardening. It is shown that the proposed method based on long short-term memory networks allowed a reasonable agreement of stress–strain curves to be obtained for cyclic deformation in a low-cycle fatigue regime. The main advantage of the proposed approach over traditional optimization schemes lies in the possibility of obtaining parameters for a new material without the necessity of conducting any further optimizations. As the power and robustness of the developed method was demonstrated for very challenging problems (cyclic deformation, crystal plasticity, self-consistent model and isotropic and kinematic hardening), it is directly applicable to other experiments and models.

Keywords:
crystal plasticity, optimization, machine learning, long short-term memory networks, self-consistent modeling, Eshelby solution, cyclic deformation, low cycle fatigue

Jóźwiak-Niedźwiedzka D., Jaskulski R., Dziedzic K., Brachaczek A., Jarząbek D., Initial Characteristics of Alkali–Silica Reaction Products in Mortar Containing Low-Purity Calcined Clay, Materials, ISSN: 1996-1944, DOI: 10.3390/ma17102207, Vol.17, No.10, pp.1-15, 2024

Abstract:
An alkali–silica reaction (ASR) is a chemical process that leads to the formation of an expansive gel, potentially causing durability issues in concrete structures. This article investigates the properties and behaviour of ASR products in mortar with the addition of low-purity calcined clay as an additional material. This study includes an evaluation of the expansion and microstructural characteristics of the mortar, as well as an analysis of the formation and behaviour of ASR products with different contents of calcined clay. Expansion tests of the mortar beam specimens were conducted according to ASTM C1567, and a detailed microscopic analysis of the reaction products was performed. Additionally, their mechanical properties were determined using nanoindentation. This study reveals that with an increasing calcined clay content, the amount of the crystalline form of the ASR gel decreases, while the nanohardness increases. The Young’s modulus of the amorphous ASR products ranged from 5 to 12 GPa, while the nanohardness ranged from 0.41 to 0.67 GPa. The obtained results contribute to a better understanding of how the incorporation of low-purity calcined clay influences the ASR in mortar, providing valuable insights into developing sustainable and durable building materials for the construction industry.

Keywords:
alkali–silica reaction, ASR products, calcined clay, mortar, expansion

Pietrzyk-Thel P., Jain A., Bochenek K., Michalska M., Basista M. A., Szabo T., Nagy P., Wolska A., Klepka M., Flexible, tough and high-performing ionogels for supercapacitor application, Journal of Materiomics, ISSN: 2352-8478, DOI: 10.1016/j.jmat.2024.01.008, pp.1-41, 2024

Abstract:
Ionogels are an attractive class of materials for smart and flexible electronics and are prepared from the combination of a polymer and ionic liquid which is entrapped in this matrix. Ionogels provide a continuous conductive phase with high thermal, mechanical, and chemical stability. However, because of the higher percentage of ionic liquids it is difficult to obtain an ionogel with high ionic conductivity and mechanical stability, which are very important from an application point of view. In this work, ionogel films with high flexibility, excellent ionic conductivity, and exceptional stability were prepared using polyvinyl alcohol as the host polymer matrix and 1-ethyl-3-methylimidazolium hydrogen sulfate as the ionic liquid using water as the solvent for energy storage application. The prepared ionogel films exhibited good mechanical stability along with sustaining strain of more than 100% at room temperature and low temperature, the ability to withstand twisting up to 360° and different bending conditions, and excellent ionic conductivity of 5.12 × 10−3 S/cm. The supercapacitor cell fabricated using the optimized ionogel film showed a capacitance of 39.9 F/g with an energy and power densities of 5.5 Wh/kg and 0.3 kW/kg, respectively confirming the suitability of ionogels for supercapacitor application.

Keywords:
Ionic liquid, Gel polymer electrolyte, Ionic conductivity, 1-Ethyl-3-methylimidazolium hydrogen sulfate, Supercapacitors

Kucharski S. J., Maj M., Ryś M., Petryk H. M., Size effects in spherical indentation of single crystal copper, INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, ISSN: 0020-7403, DOI: 10.1016/j.ijmecsci.2024.109138, Vol.272, pp.1-15, 2024

Keywords:
Hardness, Lattice rotation, Plasticity, Strain Gradient

Rezaee Hajidehi M., Ryś M., Modeling the interaction between instabilities and functional degradation in shape memory alloys, INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, ISSN: 0020-7403, DOI: 10.1016/j.ijmecsci.2024.109569, Vol.282, pp.109569-1-16, 2024

Abstract:
Localization of the stress-induced martensitic phase transformation plays an important role in the fatigue behavior of shape memory alloys (SMAs). The phenomenon of return-point memory that is observed during the subloop deformation of a partially-transformed SMA is a clear manifestation of the interaction between localized phase transformation and degradation of the functional properties. The present study aims to demonstrate this structure–material interaction in the modeling of return-point memory. It seems that this crucial aspect has been overlooked in previous modeling studies. For this purpose, we developed a gradient- enhanced model of pseudoelasticity that incorporates the degradation of functional properties in its constitutive description. The model is employed to reproduce the hierarchical return-point memory in a pseudoelastic NiTi wire under isothermal uniaxial tension with nested subloops. Additionally, a detailed analysis is carried out for NiTi strip with a more complex transformation pattern. Our study highlights the subtle morphological changes of phase transformation under different loading scenarios and the resulting implications for return-point memory.

Keywords:
Shape memory alloys,Phase transformation,Functional degradation ,Propagating instabilities,Subloop deformation,Modeling

James B., Stupkiewicz S., Indentation of a thin incompressible layer with finite friction, INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, ISSN: 0020-7683, DOI: 10.1016/j.ijsolstr.2024.112868, Vol.298, pp.112868-1-8, 2024

Abstract:
If a thin layer of an incompressible elastic material is pressed between two plane surfaces, the effective stiffness is very sensitive to the presence of frictional slip. This effect is investigated using a low-order polynomial representation of the through-thickness displacement profile. Results show good agreement with finite element studies and also show that the stiffness is significantly affected by that part of the layer [if any] outside the loaded region. The same result is then used in convolution to approximate the load-displacement response for a convex indenter.

Keywords:
Thin elastic layer,Coulomb friction,Contact mechanics

Deshpande S., Bordas S., Lengiewicz J. A., MAgNET: A graph U-Net architecture for mesh-based simulations, Engineering Applications of Artificial Intelligence, ISSN: 0952-1976, DOI: 10.1016/j.engappai.2024.108055, Vol.133 B, No.108055, pp.1-18, 2024

Abstract:
In many cutting-edge applications, high-fidelity computational models prove to be too slow for practical use and are therefore replaced by much faster surrogate models. Recently, deep learning techniques have increasingly been utilized to accelerate such predictions. To enable learning on large-dimensional and complex data, specific neural network architectures have been developed, including convolutional and graph neural networks. In this work, we present a novel encoder–decoder geometric deep learning framework called MAgNET, which extends the well-known convolutional neural networks to accommodate arbitrary graph-structured data. MAgNET consists of innovative Multichannel Aggregation (MAg) layers and graph pooling/unpooling layers, forming a graph U-Net architecture that is analogous to convolutional U-Nets. We demonstrate the predictive capabilities of MAgNET in surrogate modeling for non-linear finite element simulations in the mechanics of solids.

Keywords:
Geometric deep learning, Mesh based simulations, Finite element method, Graph U-Net, Surrogate modeling

Darban H., Luciano R., Basista M. A., Modeling frequency shifts in small-scale beams with multiple eccentric masses, Thin-Walled Structures, ISSN: 0263-8231, DOI: 10.1016/j.tws.2024.112005, Vol.201, No.Part A, pp.112005-1-112005-19, 2024

Abstract:
Studying the dynamics of small-scale beams with attached particles is crucial for sensing applications in various fields, such as bioscience, material science, energy storage devices, and environmental monitoring. Here, a stress-driven nonlocal model is presented for the free transverse vibration of small-scale beams carrying multiple masses taking into account the eccentricity of the masses relative to the beam axis. The results show excellent agreement with the experimental and numerical data in the literature. New insights into the frequency shifts and mode shapes of the first four vibrational modes of stress-driven nonlocal beams with up to three attached particles are presented. The study investigates the inverse problem of detecting the location and mass of an attached particle based on natural frequency shifts. The knowledge acquired from the present study provides valuable guidance for the design and analysis of ultrasensitive mechanical mass sensors.

Keywords:
Size effect, Mass sensor, Micro- and nanobeam, Nonlocal, Inverse problem

Huang T., Ayuningtyas Y., Wang C., Krajewski M., Lin J., Polyvinylpyrrolidone-assisted sol–gel synthesis of efficient Li2TiSiO5/C composite anodes for Li-Ion batteries, APPLIED SURFACE SCIENCE, ISSN: 0169-4332, DOI: 10.1016/j.apsusc.2024.160914, Vol.676, No.160914, pp.1-8, 2024

Abstract:
This study presents the process of developing an effective anode material for lithium-ion batteries (LIBs) by usage of Li2TiSiO5 coated with a thin layer of carbon (LTSO/C). The material was prepared through a sol–gel method, where varying amounts of polyvinylpyrrolidone (PVP) were used as a carbon source during the synthesis process. The physicochemical analysis of the LTSO/C samples indicates that as the amount of PVP used during sol–gel synthesis increases, the particle diameter of LTSO decreases. Furthermore, the analysis shows that a thin amorphous carbon layer is deposited on the LTSO surfaces, along with additional carbon networks between the LTSO particles. Based on the electrochemical analysis conducted to optimize the amount of PVP during synthesis, the resulting LTSO/C composite electrode synthesized with 1 g of PVP exhibits a specific capacity of 274.5 mAh·g−1 at 0.1C after 150 cycles, which is quite close to the theoretical capacity. In addition, this LTSO/C electrode demonstrates exceptional electrochemical performance when operated at high rates, surpassing a discharge capacity of 170 mAh g−1 up to 2C. Therefore, the LTSO/C is an excellent choice for high-performance anode material in LIBs.

Keywords:
Li2TiSiO5, Carbon layer, Polyvinylpyrrolidone, Anode material, Lithium-ion batteries, Sol–gel synthesis

Kowalczyk-Gajewska K., Maj M., Bieniek K., Majewski M., Opiela K.C., Zieliński T.G., Cubic elasticity of porous materials produced by additive manufacturing: experimental analyses, numerical and mean-field modelling, ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, ISSN: 1644-9665, DOI: 10.1007/s43452-023-00843-z, Vol.24, pp.34-1-34-22, 2024

Abstract:
Although the elastic properties of porous materials depend mainly on the volume fraction of pores, the details of pore distribution within the material representative volume are also important and may be the subject of optimisation. To study their effect, experimental analyses were performed on samples made of a polymer material with a predefined distribution of spherical voids, but with various porosities due to different pore sizes. Three types of pore distribution with cubic symmetry were considered and the results of experimental analyses were confronted with mean-field estimates and numerical calculations. The mean-field ‘cluster’ model is used in which the mutual interactions between each of the two pores in the predefined volume are considered. As a result, the geometry of pore distribution is reflected in the anisotropic effective properties. The samples were produced using a 3D printing technique and tested in the regime of small strain to assess the elastic stiffness. The digital image correlation method was used to measure material response under compression. As a reference, the solid samples were also 3D printed and tested to evaluate the polymer matrix stiffness. The anisotropy of the elastic response of porous samples related to the arrangement of voids was assessed. Young’s moduli measured for the additively manufactured samples complied satisfactorily with modelling predictions for low and moderate pore sizes, while only qualitatively for larger porosities. Thus, the low-cost additive manufacturing techniques may be considered rather as preliminary tools to prototype porous materials and test mean-field approaches, while for the quantitative and detailed model validation, more accurate additive printing techniques should be considered. Research paves the way for using these computationally efficient models in optimising the microstructure of heterogeneous materials and composites.

Keywords:
Pore configuration, Anisotropy, Elasticity, Micro-mechanics, Additive manufacturing

Nowak M., Szeptyński P., Musiał S., Maj M., Sub‑global equilibrium method for identifcation of elastic parameters based on digital image correlation results, ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, ISSN: 1644-9665, DOI: 10.1007/s43452-024-00979-6, Vol.24, pp.169-190, 2024

Abstract:
In this work, a new, simple method is presented, which enables identifcation of material properties of solids basing on the digital image correlation (DIC) measurements. It may be considered as a simplifed alternative of low computational complexity for the well-known fnite element model updating (FEMU) method and virtual felds method (VFM). The idea of the introduced sub-global equilibrium (SGE) method is to utilize the fundamental concept and defnition of internal forces and its equilibrium with appropriate set of external forces. This makes the method universal for the use in the description of a great variety of continua. The objective function is the measure of imbalance, namely the sum of squares of residua of equilibrium equations of external forces and internal forces determined for fnite-sized part of the sample. It is then minimized with the use of the Nelder–Mead downhill simplex algorithm. The efciency of the proposed SGE method is shown for two types of materials: 310 S austenitic steel and carbon-fber-reinforced polymer (CFRP). The proposed method was also verifed based on FE analysis showing error estimation.

Keywords:
Identifcation of material constant,Digital image correlation,Nelder–Mead downhill simplex algorithm,Finite element analysis,Optimization,Linear elasticity

Witecka A., Pietrzyk-Thel P., Krajewski M., Sobczak K., Wolska A., Jain A., Preparation of activated carbon/iron oxide/chitosan electrodes for symmetric supercapacitor using electrophoretic deposition: A facile, fast and sustainable approach, JOURNAL OF ALLOYS AND COMPOUNDS, ISSN: 0925-8388, DOI: 10.1016/j.jallcom.2024.174040, Vol.985, No.174040, pp.1-15, 2024

Abstract:
In this research, electrophoretic deposition (EPD) was employed to prepare a porous composite film (ACF electrode) consisting of 90 wt% activated carbon particles, 10 wt% iron oxide nanoparticles, and a chitosan as binder in a facile, fast, and sustainable manner. This micro-mesoporous composite film, with a thickness of ∼45 µm and a surface area of ∼208.1 m2g−1, was coated on a stainless steel substrate. The SEM and TEM investigations proved the homogeneous distribution of carbon microparticles and iron oxide nanoparticles in the deposit, while the EDX, XRD, Raman spectroscopy, and XPS confirmed the chemical composition. ACF electrodes were also used in a symmetric two-electrode cell configuration with a sandwiched gel polymer electrolyte - PVdF(HFP)-PC-Mg(ClO4)2 and revealed a specific capacitance of ∼54.4 F g−1, along with satisfactory energy and power density of ∼4.7 Wh kg−1 and 1.2 kW kg−1, respectively, and excellent electrochemical stability up to ∼10,000 cycles (with merely 8.5% decay by the 5000th cycle). Obtained results confirmed the stability of the used system and its possible application in the field of energy storage and conversion.

Levintant-Zayonts N., Starzyński G., Kucharski S. J., Constituting and Investigation of Ion-Implanted Protective Layer on NiTi Alloy for Mechanical and Tribological Applications, Journal of Tribology, ISSN: 0742-4787, DOI: 10.1115/1.4066204, Vol.147, No.011401, pp.1-13, 2024

Abstract:
NiTi exhibits an excellent wear resistance, which can be further enhanced by ion implantation. However, there are some limitations to the implantation effects: only a thin layer of about 100 nm can be created. In this paper, the effect of nitrogen ion implantation on the NiTi wear response is investigated. The different loads and durations of tests are taken into account to show that the implanted layer has the most beneficial effect only in a certain range of contact pressure. It was found that the wear volume changes in a nonlinear manner with respect to the load and sliding length, for both non- and implanted samples. For the latter, two distinct stages can be distinguished in the wear process: an initial stage characterized by a low wear-rate and a low coefficient of friction, and a second stage in which the wear-rate drastically increases. The duration of the first stage is longer for lower loads. This specific behavior is explained by differences in the hardness distribution, energy dissipation due to the normal load, and differences in the microstructure of the wear tracks. Our results show that the lifetime of NiTi can be improved by ion implantation, thus boding well for applications in harsh environments.

Keywords:
ion implantation, NiTi shape memory alloy, sliding wear, pseudoelasticity, abrasion, dry friction, surface treatments

Witecka A., Schmitt J., Courtien M., Gerardin C., Rydzek G., Hybrid mesoporous silica materials templated with surfactant polyion complex (SPIC) micelles for pH-triggered drug release, Microporous and Mesoporous Materials, ISSN: 1387-1811, DOI: 10.1016/j.micromeso.2023.112913, Vol.365, No.112913, pp.1-13, 2024

Abstract:
New Surfactant PolyIon Complex (SPIC) micelles were assembled by electrostatic complexation of an antibacterial cationic surfactant, cetylpyridinium chloride (CPC), and a double hydrophilic block copolymer (DHBC) containing a neutral comb block of poly(oligo(ethylene glycol)) methyl ether acrylate (PEOGA) and a weak polyacid block of poly(acrylic acid) (PAA). The corresponding SPIC micelles, with a CPC/PAA core and a PEOGA corona, were successfully used as structure directing and functionalizing agents in a soft and sustainable sol-gel strategy, yielding hybrid mesoporous silica (MS) materials with a monomodal pore size distribution centred at 2.8 nm. The influence of synthesis parameters, including the pH, concentrations and ratios of components, was systematically investigated. The obtained hybrid MS materials were intrinsically functional, with PEOGA blocks anchored in silica walls via H-bonding, while weak polyacid blocks, complexed with CPC, were confined within the mesopores. The response of the materials to pH changes (pH 7.4, 4.2 and 3) indicated remarkable stability of the anchored DHBC, while CPC was selectively released under the acidic conditions typical of orodental biofilm microenvironments. This result is noteworthy, since the release of encapsulated amphiphilic drugs into water is less favorable than that of hydrophilic drugs. Owing to the control of their pore and functionality properties, ordered hybrid silica materials templated and functionalized with SPIC systems will be materials of choice for developing pH-responsive biomedical devices using wet processing techniques

Keywords:
Double hydrophilic block copolymer, Cooperative self-assembly, Surfactant-polyion complex micelle, Stimuli-responsive nanomaterials, Sustainable, Sol-gel synthesis

Ciurans-Oset M., Flasar P., Jenczyk P., Jarząbek D. M., Mouzon J., Akhtar F., Role of the microstructure and the residual strains on the mechanical properties of cast tungsten carbide produced by different methods, Journal of Materials Research and Technology, ISSN: 2238-7854, DOI: 10.1016/j.jmrt.2024.04.067, Vol.30, pp.3640-3649, 2024

Abstract:
Cast tungsten carbide (CTC) is a biphasic, pearlitic-like structure composed of WC lamellae in a matrix of W2C. Besides excellent flowability, spherical CTC powders exhibit superior hardness and wear resistance. Nevertheless, the available literature generally fails to explain the physical mechanisms behind such a phenomenon. In the present work, the microstructure and the mechanical properties of the novel centrifugally-atomized spherical CTC have been extensively investigated. This material exhibited an extremely fine microstructure, with WC lamellae of 27–29 nm in thickness and bulk lattice strains of 1.0–1.4 %, resulting in a microindentation hardness of 31.4 ± 1.6 GPa. The results of this study clearly show that centrifugally-atomized CTC is mechanically superior to both spheroidized CTC and conventional cast-and-crushed CTC. In addition, the effect of a series of heat treatments on the bulk fracture toughness and the fatigue life of entire CTC particles was also investigated. The reduction of residual stresses in the bulk of particles upon annealing dramatically increased the indentation fracture toughness, whereas the bulk microindentation hardness remained essentially unaffected. Regarding the fatigue life of entire particles under uniaxial cyclic compressive loading, local phase transformation phenomena at the surface of the particles upon heat treatment were concluded to play the most critical role. Indeed, the cumulative fatigue damage was minimized in surface-carburized CTC powders, where compressive stresses were induced at the outermost surface.

Keywords:
Cast tungsten carbide, Microindentation hardness, X-ray diffraction, Lattice microstrains, Dislocation density, Compression

Rezaee Hajidehi M., Modeling of localized phase transformation in pseudoelastic shape memory alloys accounting for martensite reorientation, EUROPEAN JOURNAL OF MECHANICS A-SOLIDS, ISSN: 0997-7538, DOI: 10.1016/j.euromechsol.2024.105376, Vol.107, pp.105376-1-19, 2024

Abstract:
A reliable prediction of the pseudoelastic behavior necessitates the involvement of martensite reorientation in the model. This is important not only under non-proportional loading but in general when the phase transformation proceeds in a localized manner, which results in complex local deformation paths. In this work, an advanced model of pseudoelasticity is developed within the incremental energy minimization framework. A novel enhancement of the model over its original version lies in the formulation of a suitable rate-independent dissipation potential that incorporates the dissipation due to martensitic phase transformation and also due to martensite reorientation, thus yielding an accurate description of the inelastic transformation strain. The finite-element implementation of the model relies on the augmented Lagrangian treatment of the non-smooth incremental energy problem. Thanks to the micromorphic regularization, the related complexities are efficiently handled at the local level, leading to a robust finite-element model. Numerical studies highlight the predictive capabilities of the model. The characteristic mechanical behavior of NiTi tube under non-proportional tension– torsion and the intricate transformation evolution under pure bending are effectively captured by the model. Additionally, a detailed analysis is carried out to elucidate the important role of martensite reorientation in promoting the striations of the phase transformation front.

Keywords:
Shape memory alloys,Phase transformation,Martensite reorientation,Strain localization,Finite-element method

Węglewski W., Sequeira A., Bochenek K., Rosc J., Brunner R., Basista M.A., Finite element modeling of thermal residual stresses in functionally graded aluminum-matrix composites using X-ray micro-computed tomography, FINITE ELEMENTS IN ANALYSIS AND DESIGN, ISSN: 0168-874X, DOI: 10.1016/j.finel.2024.104239, Vol.241, No.104239, pp.1-16, 2024

Abstract:
Metal-ceramic composites by their nature have thermal residual stresses at the micro-level, which can compromise the integrity of structural elements made from these materials. The evaluation of thermal residual stresses is therefore of continuing research interest both experimentally and by modeling. In this study, two functionally graded aluminum alloy matrix composites, AlSi12/Al2O3 and AlSi12/SiC, each consisting of three composite layers with a stepwise gradient of ceramic content (10, 20, 30 vol%), were produced by powder metallurgy. Thermal residual stresses in the AlSi12 matrix and the ceramic reinforcement of the ungraded and graded composites were measured by neutron diffraction. Based on the X-ray micro-computed tomography (micro-XCT) images of the actual microstructure, a series of finite element models were developed to simulate the thermal residual stresses in the AlSi12 matrix and the reinforcing ceramics Al2O3 and SiC. The accuracy of the numerical predictions is high for all cases considered, with a difference of less than 5 % from the neutron diffraction measurements. It is shown numerically and validated by neutron diffraction data that the average residual stresses in the graded AlSi12/Al2O3 and AlSi12/SiC composites are lower than in the corresponding ungraded composites, which may be advantageous for engineering applications.

Keywords:
Finite element modeling,Micro-XCT,Thermal residual stress,Hot pressing,Aluminum matrix composites

Gaurav A., Das A., Paul A., Jain A., Boruah B., Jalebi M., Could halide perovskites revolutionalise batteries and supercapacitors: A leap in energy storage, Journal of Energy Storage, ISSN: 2352-152X, DOI: 10.1016/j.est.2024.111468, Vol.88, No.111468, pp.1-22, 2024

Abstract:
Metal halide perovskites have rapidly emerged as a revolutionary frontier in materials science, catalyzing breakthroughs in energy storage technology. Originating as transformative entities in the field of solar cells, these perovskites have surpassed conventional boundaries. This comprehensive review embarks on a journey through the intriguing potentials of energy storage, driven by the exceptional properties of perovskite materials. We delve into three compelling facets of this evolving landscape: batteries, supercapacitors, and the seamless integration of solar cells with energy storage. In the realm of batteries, we introduce the utilization of perovskites, with a specific focus on both lead and lead-free halide perovskites for conciseness. Leveraging superior electrical properties such as high ionic conductivity (ranging from 10−3 to 10−4 Scm−1 for Li-ion) and diverse structural dimensions coupled with remarkable diffusion coefficients (2.68 × 10−8 cm2s−1 and 3.63 × 10−9 cm2s−1) for Chloride and Iodide-based halide perovskites, respectively, we explore the immense potential of perovskites as electrodes compared to other host materials such as layered oxide, carbon, etc., specifically for Al-ion, Zn-ion, and Li-ion batteries application, paving the way for the next generation of energy storage devices. In the domain of supercapacitors, we discuss the application of halide perovskites, highlighting both their advantages and limitations. We also provide a brief overview of the significant progress made in the supercapacitor domain using perovskite materials over the years. Additionally, we venture into unexplored territories, emphasizing the potential integration of solar cells and energy storage systems, delving into innovative concepts such as photo-accelerated capacitors/supercapacitors and photo-accelerated batteries. Importantly, we presented a detailed analysis of the impact of the perovskite composition on different energy storage applications. Ultimately, we outline the significant advantages, recognize the existing limitations, and stimulate imagination concerning the boundless future potential of halide perovskites in the energy storage domain, fostering a scientific and innovative perspective that contributes to the ongoing research and practical application of perovskite materials.

Keywords:
Metal halide perovskite, Energy storage, Battery, Supercapacitors, Perovskite solar cells-batteries

Staszczak M., Urbański L., Cristea M., Ionita D., Pieczyska E.A., Investigation of Shape Memory Polyurethane Properties in Cold Programming Process Towards Its Applications, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym16020219, Vol.16, No.2, pp.219-1-219-20, 2024

Abstract:
Thermoresponsive shape memory polymers (SMPs) with the remarkable ability to remember a temporary shape and recover their original one using temperature have been gaining more and more attention in a wide range of applications. Traditionally, SMPs are investigated using a method named often “hot-programming”, since they are heated above their glass transition temperature (Tg) and after that, reshaped and cooled below Tg to achieve and fix the desired configuration. Upon reheating, these materials return to their original shape. However, the heating of SMPs above their Tg during a thermomechanical cycle to trigger a change in their shape creates a temperature gradient within the material structure and causes significant thermal expansion of the polymer sample resulting in a reduction in its shape recovery property. These phenomena, in turn, limit the application fields of SMPs, in which fast actuation, dimensional stability and low thermal expansion coefficient are crucial. This paper aims at a comprehensive experimental investigation of thermoplastic polyurethane shape memory polymer (PU-SMP) using the cold programming approach, in which the deformation of the SMP into the programmed shape is conducted at temperatures below Tg. The PU-SMP glass transition temperature equals approximately 65 ◦C. Structural, mechanical and thermomechanical characterization was performed, and the results on the identification of functional properties of PU-SMPs in quite a large strain range beyond yield limit were obtained. The average shape fixity ratio of the PU-SMP at room temperature programming was found to be approximately 90%, while the average shape fixity ratio at 45 ◦C (Tg − 20 ◦C) was approximately 97%. Whereas, the average shape recovery ratio was 93% at room temperature programming and it was equal to approximately 90% at 45 ◦C. However, the results obtained using the traditional method, the so-called hot programming at 65 ◦C, indicate a higher shape fixity value of 98%, but a lower shape recovery of 90%. Thus, the obtained results confirmed good shape memory properties of the PU-SMPs at a large strain range at various temperatures. Furthermore, the experiments conducted at both temperatures below Tg demonstrated that cold programming can be successfully applied to PU-SMPs with a relatively high Tg. Knowledge of the PU-SMP shape memory and shape fixity properties, estimated without risk of material degradation, caused by heating above Tg, makes them attractive for various applications, e.g., in electronic components, aircraft or aerospace structures.

Keywords:
polyurethane shape memory polymer, cold programming, thermal expansion, shape fixity, shape recovery

Staszczak M., Urbański L., Gradys A. D., Cristea M., Pieczyska E. A., Nucleation, Development and Healing of Micro-Cracks in Shape Memory Polyurethane Subjected to Subsequent Tension Cycles, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym16131930, Vol.16, No.13, pp.1-22, 2024

Abstract:
Thermoresponsive shape memory polymers (SMPs) have garnered increasing interest for their exceptional ability to retain a temporary shape and recover the original configuration through temperature changes, making them promising in various applications. The SMP shape change and recovery that happen due to a combination of mechanical loading and appropriate temperatures are related to its particular microstructure. The deformation process leads to the formation and growth of micro-cracks in the SMP structure, whereas the subsequent heating over its glass transition temperature Tg leads to the recovery of its original shape and properties. These processes also affect the SMP microstructure. In addition to the observed macroscopic shape recovery, the healing of micro-crazes and micro-cracks that have nucleated and developed during the loading occurs. Therefore, our study delves into the microscopic aspect, specifically addressing the healing of micro-cracks in the cyclic loading process. The proposed research concerns a thermoplastic polyurethane shape memory polymer (PU-SMP) MM4520 with a Tg of 45 °C. The objective of the study is to investigate the effect of the number of tensile loading-unloading cycles and thermal shape recovery on the evolution of the PU-SMP microstructure. To this end, comprehensive research starting from structural characterization of the initial state and at various stages of the PU-SMP mechanical loading was conducted. Dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS) and scanning electron microscopy (SEM) were used. Moreover, the shape memory behavior in the thermomechanical loading program was investigated. The obtained average shape fixity value was 99%, while the shape recovery was 92%, which confirmed good shape memory properties of the PU-SMP. Our findings reveal that even during a single loading-unloading tension cycle, crazes and cracks nucleate on the surface of the PU-SMP specimen, whereas the subsequent temperature-induced shape recovery process carried out at the temperature above Tg enables the healing of micro-cracks. Interestingly, the surface of the specimen after three and five loading-unloading cycles did not exhibit crazes and cracks, although some traces of cracks were visible. The traces disappeared after exposing the material to heating at Tg + 20 °C (65 °C) for 30 min. The crack closure phenomenon during deformation, even without heating over Tg, occurred within three and five subsequent cycles of loading-unloading. Notably, in the case of eight loading-unloading cycles, cracks appeared on the surface of the PU-SMP and were healed only after thermal recovery at the particular temperature over Tg. Upon reaching a critical number of cycles, the proper amount of energy required for crack propagation was attained, resulting in wide-open cracks on the material’s surface. It is worth noting that WAXS analysis did not indicate strong signs of typical highly ordered structures in the PU-SMP specimens in their initial state and after the loading history; however, some orientation after the cyclic deformation was observed.

Keywords:
polyurethane shape memory polymer, glass transition temperature, tensile loading cycles, structure analysis, micro-cracks, healing

Mościcki T. P., Psiuk R., Jarząbek D. M., Ciemiorek-Bartkowska M., Kulikowski K., Jasiński J., Włoczewski M., Lewandowska-Szumieł M., Effect of titanium and deposition parameters on microstructure and mechanical properties of W-Ti-B thin films deposited by High Power Impulse Magnetron Sputtering, SURFACE AND COATINGS TECHNOLOGY, ISSN: 0257-8972, DOI: 10.1016/j.surfcoat.2024.130915, Vol.485, No.130915, pp.1-13, 2024

Abstract:
Tungsten diboride alloyed with transition metals provides an opportunity to obtain exceptional mechanical, physical, and chemical properties. We report a strategy for designing and synthesizing of superhard and low-compressible ceramic thin films with increased toughness and lowered residual stresses (σ < −0.9 GPa) deposited with high-power impulse magnetron sputtering (HiPIMS) from one target. The addition of 7–12 % titanium promotes additional strengthening mechanisms of the layers in one material, leading to the improvement of wear resistance compared to an alloyed WB2-z yet at even higher hardness 43.8 ± 2.1 GPa and nanoindentation toughness 4.9 ± 0.2 MPa√m. The compression of the micropillar shows that titanium addition changed the type of nanoindentation from cracking along the slip plane to bulging on the top of the pillar and next the crack initiation along column boundaries. The highest adhesion of the layers is obtained for addition of 7 % titanium and in all cases the wear has abrasive character. The controlled use of 200 μs pulses during synthesis with HiPIMS allows for an increase in the deposition rate and maintaining exceptional mechanical properties of the layers even at a substrate temperature of 300 °C.

Keywords:
Ternary transition metal diboride thin films, Mechanical properties, HiPIMS magnetron sputtering, Wear resistance and adhesion

Bochenek K., Arneitz S., Sommitsch C., Basista M.A., Comparison of Mechanical Properties of Bulk NiAl-Re-Al2O3 Intermetallic Material Manufactured by Laser Powder Bed Fusion and Hot Pressing, Journal of Materials Engineering and Performance, ISSN: 1059-9495, DOI: 10.1007/s11665-024-09657-3, pp.1-10, 2024

Abstract:
The low fracture toughness of NiAl at room temperature is one of the critical issues limiting its application in aircraft engines. It has been previously shown that a small addition of rhenium and alumina significantly improves the fracture toughness of hot-pressed NiAl. In this work, NiAl with an admixture of rhenium and alumina was produced by laser powder bed fusion additive technology (LPBF). The purpose was to compare the fracture toughness, bending strength, and microhardness of the NiAl-Re-Al2O3 material produced by LPBF and hot pressing (HP). Our results show that the LPBF material has lower fracture toughness and bending strength compared to its hot-pressed equivalent. Microcracks generated by thermal stresses during the LPBF process were the primary cause of this behavior. To improve the LPBF material, a post-processing by HP was applied. However, the fracture toughness of the (LPBF + HP) material remained at 50% of the KIC of the HP material. This study supports hot pressing as a suitable processing method for NiAl with rhenium and alumina additions. However, a hybrid approach combining LPBF and HP proved to be highly effective on the raw NiAl powder, resulting in superior fracture toughness of the final material compared to that consolidated by singular HP.

Keywords:
NiAl intermetallic,additive manufacturing ,hot pressing ,mechanical properties

Rawat S., Singh P., Jain A., Song S., Yahya M., Savilov S., Diantoro M., Michalska M., Polu A., Singh R., Ionic liquid (1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate) doped polyethylene polymer electrolyte for energy devices, Journal of Materials Science: Materials in Electronics, ISSN: 0957-4522, DOI: 10.1007/s10854-024-13397-4, Vol.35, No.1643, pp.1-10, 2024

Abstract:
This paper provides a comprehensive overview of the influence of 1-Butyl-1-Methylpyrrolidinium Trifluoromethanesulfonate (BMPyrrOTf)-ionic liquid on a new polymer electrolyte where Polyethylene oxide (PEO) as host and ammonium iodide (NH4I) as salt. These IL-doped solid polymer electrolyte were prepared using solution cast technique. Various characterisation techniques have been utilized to evaluate the qualitative and quantitative estimation of polymer electrolyte like Polarized microscopy (POM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Linear sweep voltammetry (LSV), Ionic transference no. (tion) and Impedance spectroscopy. Doping IL increases conductivity and highest achieve at 8 wt% of BMPyrrOTF with conductivity value reaches upto 4.15 × 10–5 S/cm at. Using Wagner’s polarization method, Ionic transference measurement support ionic conduction while stable potential window has further affirmed good electrochemical stability of films. The highest conducting IL-enriched polymer electrolyte sandwiched low-cost dye-sensitized solar cells (DSSCs) and electric double layer capacitors (EDLCs) have been developed, and their performance is conveniently appropriate.

Zargarian S., Kupikowska-Stobba B., Kosik-Kozioł A., Bartolewska M., Zakrzewska A., Rybak D., Bochenek K., Osial M., Pierini F., Light-responsive biowaste-derived and bio-inspired textiles: Dancing between bio-friendliness and antibacterial functionality, Materials Today Chemistry, ISSN: 2468-5194, DOI: 10.1016/j.mtchem.2024.102281, Vol.41, pp.102281-1-15, 2024

Abstract:
Functional antibacterial textiles fabricated from a hybrid of organic waste-derived and bio-inspired materials offer sustainable solutions for preventing microbial infections. In this work, we developed a novel antibacterial textile created through the valorization of spent coffee grounds (SCG). Electrospinning and electrospraying techniques were employed to integrate the biowaste within a polymeric nanofiber matrix, ensuring uniform particle distribution and providing structural support for enhanced applicability. Modification with polydopamine (PDA) significantly enhanced the textile's photothermal performance. Specific attention was paid to understanding the relation between temperature change and key variables, including the surrounding liquid volume, textile layer stacking, and applied laser power. Developed platforms demonstrated excellent photothermal stability. While the SCG-based textile demonstrated exceptional biocompatibility, the PDA-modified textile effectively eradicated Staphylococcus aureus (S. aureus) under near-infrared (NIR) irradiation. The developed textiles in our work demonstrate a dynamic balance between biocompatibility and on-demand antibacterial functionality, offering adaptable solutions in accordance with the desired application.

Keywords:
Organic waste valorization, Spent coffee grounds, Micro-nanostructured textiles, Bio-inspired photothermal agents, Polydopamine, Antibacterial textiles

Mousavisogolitappeh H., Amini C., Efficient homogenization of honeycomb sandwich panels using orthotropic core simplification and Finite Element-based method: A comparative study, Journal of Composite Materials, ISSN: 0021-9983, DOI: 10.1177/002199832412404, pp.1-13, 2024

Abstract:
Composite materials, particularly honeycomb composites, are widely utilized in various industries, including aerospace, due to their high energy absorption against the impact and exceptional strength-to-weight ratio. This study aims to leverage the plastic and elastic properties of these materials to develop a simplified numerical model that incorporates orthotropic properties for core modeling. By doing so, the need for detailed honeycomb structure modeling is eliminated, resulting in reduced computational costs and time. A comprehensive three-dimensional finite element model, accounting for structural intricacies, is presented based on experimental data from a reputable source (isotropic model) and its equivalent finite element model (orthotropic model). The model is validated by the experimental results, demonstrating good agreement. The study also investigates parameters such as energy absorption, the internal energy of the core and faces, maximum displacement, and maximum contact force under low-velocity impact scenarios with spherical and cylindrical projectiles. These findings highlight the effectiveness of the orthotropic model, particularly in showcasing greater energy absorption in the core of the sandwich panel when subjected to a cylindrical impactor.

Keywords:
honeycomb, sandwich panel, homogenization, finite element analysis, impact

Jain A., Michalska M., Enhanced electrochemical properties of multiwalled carbon nanotubes modified with silver nanoparticles for energy storage application, MATERIALS CHEMISTRY AND PHYSICS, ISSN: 0254-0584, DOI: 10.1016/j.matchemphys.2024.129200, Vol.317, No.129200, pp.1-9, 2024

Abstract:
This work reports an easy, straightforward, and cost-effective method to synthesize a composite material using multiwalled carbon nanotubes (MWCNTs) and silver nanoparticles (Ag NPs) for application as an electrode in supercapacitors. The objective of this work was to enhance the charge transfer mechanism in supercapacitor cells by introducing the conductive particles in the MWCNT framework. The pivotal studies, like scanning (SEM), and transmission (TEM) electron microscopy, X-ray diffraction (XRD), Raman, and X-ray photoelectron (XPS) spectroscopy confirmed the formation of the composite as well as a successful deposition of Ag NPs on MWCNT. The surface area of the composite was evaluated by using the N2 adsorption-desorption studies and it was found to be of the order of 358 m2 g−1. Electrochemical studies were performed using a two-electrode system. Magnesium ion-based polymer gel electrolyte was used as an electrolyte material. The single electrode-specific capacitance was observed to be ∼31.9 F g−1 with power density and energy density values of ∼4.4 kW kg−1 and 1.2 Wh kg−1, respectively, at a current density of 0.46 A g−1. The cell was stable up to ∼5000 charge-discharge cycles with ∼96% of capacitance retention at the end of 5000 cycles.

Keywords:
Supercapacitor, Gel polymer electrolyte, MWCNTs

Krajewski M., Lewińska S., Kubacki J., Sikora M., Sobczak K., Tokarczyk M., Ślawska-Waniewska A., Solvent-depended magnetic-field-induced synthesis of iron nanochains, Materials Letters, ISSN: 0167-577X, DOI: 10.1016/j.matlet.2024.137533, Vol.377, No.137533, pp.1-4, 2024

Abstract:
This work presents a synthesis of iron nanochains through magnetic-field-induced reduction reaction performed with sodium borohydride in water, ethanol and isopropanol. After their preparation, the nanomaterials obtained in three different processes are washed several times in ethanol and acetone to remove side-products. The performed cleaning step is very sufficient for water-based synthesis of iron nanochains. In contrary, the nanostructures obtained in ethanol and isopropanol contain a significant amount of sodium chlorides which is hard to dispose. Moreover, the use of ethanol and isopropanol solvents causes the reduction of nanochains’ diameters. Both the presence of sodium chlorides and the reduction of diameter size result in the decrease of saturation magnetization of iron nanochains and the increase of their coercivities.

Keywords:
One-dimensional nanostructures, Iron nanochains, Magnetic materials, Magnetic-field-induced synthesis

Olusegun S., Souza Guilhermina de O., Sutuła S., Osial M., Krajewski M.^♦, Pękała M., Sobczak K., Felis E., Krysiński P., Methotrexate anti-cancer drug removal using Gd-doped Fe3O4: Adsorption mechanism, thermal desorption and reusability, Groundwater for Sustainable Development, ISSN: 2352-801X, DOI: 10.1016/j.gsd.2024.101103, Vol.25, pp.1-9, 2024

Keywords:
Adsorption,Thermal desorption,Gd-doped Fe3O4,Methotrexate

Michalska M., Pavlovsky J., Scholtzova E., Peter S., Vlastimil M., Bochenek K., Jain A., Koki C., Takeharu Y., Hirotomo N., A facile approach for fabricating g-C3N4-based materials as metal-free photocatalysts, Results in Engineering, ISSN: 2590-1230, DOI: 10.1016/j.rineng.2024.103109, Vol.24, No.103109, pp.1-14, 2024

Abstract:
This study presents a novel, straightforward approach for synthesizing graphitic carbon nitrides (g-C3N4, g-CN) from melamine, requiring merely 30 min of thermal holding at temperatures ranging from 400 to 550 °C in an atmosphere comprising either nitrogen or air. Elemental analysis, X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), diffuse reflectance (UV–Vis DRS), photoluminescence (PL) spectroscopy and scanning electron microscopy (SEM) were employed to assess the quality of the as-prepared powders. Furthermore, theoretical calculations utilizing the Density Functional Theory (DFT) method were conducted to reinforce the experimental findings of the research. A further investigation of the thermal stability of the selected sample was conducted using a unique combination of thermogravimetry–coupled with differential scanning calorimetry, quadrupole mass spectrometry (TG-DSC-MS) and advanced temperature-programmed desorption (TPD) analyzes. The current study focuses on the effect of synthesis conditions (temperature and nitrogen/air environment) on the structure, morphology, and photocatalytic performance of g-C3N4 compounds synthesized using this approach. The g-C3N4-based materials were examined as potential photocatalysts using the acid orange 7 (AO7) photodegradation methodology. To enable comparison of the photodegradation experiments, two separate lamps with wavelengths of 360 nm (UV light) and 420 nm (VIS light) were utilized. The primary objective was to present a novel method for the synthesis of g-C3N4-based materials. This was achieved by demonstrating that organic composites generated at lower temperatures have the best photocatalytic capabilities. Furthermore, the approach to achieving high-quality photocatalysts was shown to be cost-effective, environmentally friendly, and scalable.