Instytut Podstawowych Problemów Techniki

Podulka P., Macek W., Zima B., Kopeć M., Ricardo B., Achtelik H., Fracture surface topography measurements analysis of low-alloyed corrosion resistant steel after bending-torsion fatigue tests, Precision Engineering, ISSN: 1873-2372, DOI: 10.1016/j.precisioneng.2024.07.002, pp.1-34, 2024

Abstract:
In this paper, an assessment of a topography measurement method for fracture surfaces of 10HNAP steel after bending-torsion fatigue tests was performed. Surface roughness was measured by using a non-contact Focus Variation Microscopy (FVM) technique in which the non-measured points (NMPs) and outliers (spikes) were removed by the application of general methods. The results revealed, that the optical measurement method introduced variations in the high-frequency errors, considered as noise within the selected bandwidth. Therefore, the minimization of the high-frequency noise (HFN) was proposed based on an extensive examination of ISO 25178 roughness parameters. Additionally, a general S-filter was applied, as recommended by international standards and commercial software. It was used to identify and remove noise from the measured data after pre-processing. Consequently, levelling and eliminating of NMPs and spikes was successfully performed. Subsequently, the results obtained by using various filters were compared to further assess the impact of different filtration bandwidths. Finally, the proposed procedure was validated by implementing different general functions, such as autocorrelation (ACF), power spectral densities (PSD), and texture direction (TD). It was concluded, that coupled characteristics, including profile and areal measurements, should be studied simultaneously since they are necessary to analyze the fracture surfaces comprehensively.

Keywords:
bending-torsion fatigue ,surface topography ,roughness ,non-measured points ,outliers ,high-frequency noise,measurement errors

Kopeć M., Brodecki A., Kowalewski Z.L., Quantitative digital image correlation approach for the monitoring of fatigue damage development in 10CrMo9-10 steel in the as-received state and after extended service, MEASUREMENT, ISSN: 0263-2241, DOI: 10.1016/j.measurement.2024.114926, Vol.234, No.114926, pp.1-9, 2024

Abstract:
In this paper, the quantitative Digital Image Correlation (DIC) approach was used to study the long-time degradation of two different states of 10CrMo9-10 (10H2M) power engineering steel. The specimens subjected to cyclic loading (R = 0) were monitored by using the DIC technique. The data obtained from DIC measurements were presented in form of strain distributions for specified, independent points within the strain gauge of specimens. Furthermore, the strain profiles were extracted for the particular stages of fatigue damage development (FDD). The presented methodology provides a different approach of DIC application, in which, the data could be treated more quantitative than qualitative.

Keywords:
Power engineering steel, Fatigue, Damage

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

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.

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.

Kaczmarek A., Wisniewska A., Mościcki T. P., Hoffman J., The Luminescence of Laser-Produced Carbon Nanodots: The Effect of Aggregation in PEI Solution, Materials, ISSN: 1996-1944, DOI: 10.3390/ma17071573, Vol.17, No.7, pp.1-15, 2024

Abstract:
Carbon nanodots (CNDs) produced in pure water by the ablation of graphite with a nanosecond laser pulse exhibit weak photoluminescence. A small addition of polyethyleneimine (PEI) to the aqueous suspension of CNDs causes a significant increase in emissions. This paper presents experimental and theoretical studies of the emission properties of CND/PEI systems. The obtained CNDs responded to even trace amounts of PEI in solution (~0.014% v/v), resulting in a significant increase in the initial weak blue emission of CNDs and PEI taken separately. Morphology and size measurements showed that particle aggregation occurred in the presence of the polymer. A decrease in the calculated Stokes shift values was observed with increasing PEI content in the solution. This indicates a reduction in the number of non-radiative transitions, which explains the increase in the emission intensity of the CND/PEI systems. These results therefore confirmed that the increase in the emission of CND/PEI systems is caused by particle aggregation. Kinetic studies proved that the process is controlled mainly by diffusion, the initial stage of which has a dominant influence on determining the optical properties of the system.

Keywords:
aggregation-induced emission, carbon nanodots, polyethyleneimine, intrinsic fluorescence, adsorption kinetic study

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

Jaskulski R., Liszka K., Jóźwiak-Niedźwiedzka D., Multifaceted Analysis of the Thermal Properties of Shielding Cement-Based Composites with Magnetite Aggregate, Materials, ISSN: 1996-1944, DOI: 10.3390/ma17122936, Vol.17, No.2936, pp.1-19, 2024

Abstract:
The paper presents and discusses the results of a study of the thermal properties of cement composites with different contents of magnetite aggregate (0%, 20%, 40% and 60% by volume). The effect of grain size on the evaluated thermal properties was also investigated. For this purpose, concrete containing 50% by volume of magnetite aggregate with four different fractions (1–2 mm, 2–4 mm, 4–8 mm and 8–16 mm) was used. Thermal parameters were evaluated on specimens fully saturated with water and dried to a constant mass at 65 °C. The series with varying grain sizes of magnetite achieved thermal conductivity values in the range of 2.76–3.03 W/(m·K) and 2.00–2.21 W/(m·K) at full water saturation and after drying to a constant mass, respectively. In the case of the series with 20% magnetite by volume, the thermal conductivity was 2.65 W/(m·K) and 1.99 W/(m·K) for the material fully saturated with water and dried to a constant mass, respectively. The series with a 60% volume share of magnetite obtained values of this parameter of 3.47 W/(m·K) and 2.66 W/(m·K), respectively, under the same assumptions.

Keywords:
shielding concrete, thermal properties, magnetite aggregate

Macek W., Kopeć M., Laska A., Kowalewski Z. L., Entire fracture surface topography parameters for fatigue life assessment of 10H2M steel, Journal of Constructional Steel Research, ISSN: 1873-5983, DOI: 10.1016/j.jcsr.2024.108890, Vol.221, No.108890, pp.1-11, 2024

Abstract:
In this paper, the entire fracture surface approach was used to assess an effect of 280,000 h of exploitation under internal pressure of 2.9 MPa and high temperature of 540 °C on the fatigue response of 10H2M (10CrMo9–10) power engineering steel. The mechanical testing was carried out on the hourglass specimens produced from the as-received, unused pipeline and the same material after long-time exploitation. The uniaxial tensile tests were performed to establish the stress amplitude for subsequent force controlled, fatigue testing in the range from ±250 MPa to ±400 MPa under the frequency of 20 Hz. Since the exploited 10H2M steel was characterized by significantly lower mechanical properties, different damage mechanisms responsible for specimen failure were revealed through fracture surface analysis. The fracture surface topography evaluation was performed with a 3D non-contact measuring system. It was found, that the exploitation state has a strong impact on the fatigue life and fracture characteristics since the significant drop in lifespan of about 300 %–400 % was found for the material after prolonged service. Finally, the proposed surface topography parameter was related to the stress amplitude in order to estimate the fatigue life for the steel in question.

Keywords:
fatigue , 10H2M steel , Mechanical properties , Surface topography

Kopeć M., Dubey Ved P., Pawlik M., Wood P., Kowalewski Z.L., Experimental identification of yield surface for additively manufactured stainless steel 316L under tension–compression-torsion conditions considering its printing orientation, Manufacturing Letters, ISSN: 2213-8463, DOI: 10.1016/j.mfglet.2024.07.003, Vol.41, pp.28-32, 2024

Abstract:
Stainless steel 316L tubes and bars were additively manufactured (AM) by using the Laser Powder Bed Fusion Melting (LPBF-M) method in three orientations. As-built specimens were then machined and the initial yield surface was determined for three printing orientations based on the yield stress definition for 0.005 % plastic offset strain. The as-received, wrought material was additionally tested using the same tension–compression-torsion conditions to compare the mechanical behaviour of AM and wrought SS316L. The sizes of yield surfaces elaborated for LPBF-M specimens increased along the tensile and compressive directions and shrunk when torsion was applied, as compared to the as-received specimen.

Keywords:
Stainless steel ,Yield surface ,Additive manufacturing

Liu X., Jin S., Ming M., Fan C., Liu H., Politis D.J., Kopeć M., A high throughput in-situ measurement of heat transfer in successive non-isothermal forming of sheet alloys, Journal of Manufacturing Processes, ISSN: 1526-6125, DOI: 10.1016/j.jmapro.2024.08.048, Vol.129, pp.77-91, 2024

Abstract:
The measurement and control of the heat transfer of sheet alloys in successive non-isothermal forming cycles is crucial to achieve the desired post-form properties and microstructure, which could not as of yet be realized by using traditional test facilities. In the present research, a novel heat transfer measurement facility was designed to generate and subsequently measure the in-situ heat transfer from a sheet alloy to multi-mediums such as forming tools, air, lubricant and coating. More importantly, the facility was able to use a single sheet alloy sample to perform successive non-isothermal forming cycles, and subsequently obtain high throughput experimental results including the temperature evolution, cooling rate, mechanical properties and microstructures of the alloy. The high throughput in-situ heat transfer measurement facility identified that the cooling rate of AA7075 was 152 °C/s and the mechanical strength was over 530 MPa in the 1st forming cycle. However, it decreased to less than the critical value of 100 °C/s in the successive 10th forming cycle, leading to a low mechanical strength of only 487 MPa. The identified variations that occur in the successive non-isothermal forming cycles would improve the consistency and accuracy of part performance in large-scale manufacturing.

Keywords:
High throughput in-situ measurement,Heat transfer,Successive non-isothermal forming,Sheet alloys,Microstructure

Kopeć M., Digital image correlation approach for low-cycle fatigue life monitoring of 13HMF power engineering steel, Optics and Lasers in Engineering, ISSN: 0143-8166, DOI: https://doi.org/10.1016/j.optlaseng.2024.108448, Vol.181, No.108448, pp.1-10, 2024

Abstract:
In this paper, strain evolution of 13HMF power engineering steel was analysed during force-controlled low cycle fatigue (LCF). The material performance under cyclic loading was monitored by using Digital Image Correlation (DIC) technique for different values of stress amplitude exceeding the yield strength of the material significantly. Data collected from DIC was compared to the extensometer ones to confirm the effectiveness of the proposed approach. Finally, the cloud data reflecting the fatigue performance of 13HMF was generated in the form of strain-stress amplitude - service life distribution map.

Keywords:
Fatigue,Mechanical properties,Strain analysis

Psiuk R., Chrzanowska-Giżyńska J., Denis P., Wyszkowska E., Wiśniewska M., Lipińska M., Wojtiuk E., Kurpaska Ł., Smolik J., Mościcki T. P., Microstructural and properties investigations of tantalum-doped tungsten diboride ceramic coatings via HiPIMS and RF magnetron sputtering, ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, ISSN: 1644-9665, DOI: 10.1007/s43452-024-01050-0, Vol.24, No.239, pp.1-16, 2024

Abstract:
In this work, tantalum-doped tungsten boride ceramic coatings were deposited from a single sputtering target with the radio frequency (RF) and high-power impulse magnetron sputtering (HiPIMS) methods. Two-inch torus targets were synthesised from pure elements with the spark plasma sintering (SPS) method with a stoichiometric composition of W1-xTaxB2.5 (x = 0, 0.08, 0.16, 0.24). Films were deposited with RF and HiPIMS power suppliers at process temperatures from RT to 600 °C. The substrate heating and the energy of the ionised material impacting the substrate increase the surface diffusivity of adatoms and are crucial in the deposition process. The results of SEM and XRD investigations clearly show that the addition of tantalum also changes the microstructure of the deposited films. The coatings without tantalum possess a finer microstructure than those with 24% of tantalum. The structure of films is homogeneous along the film thickness and composed mainly of columns with a (0001) preferred orientation. Deposited coatings are composed mainly of P6/mmm α-WB2 structures. The analysis of nanoindentation results allowed us to determine that ceramic coatings obtained with the HiPIMS method possess hardness above 41 GPa and a ratio of hardness to reduced Young modulus above 0.1. The thickness of HiPIMS-deposited films is relatively small: only around 60% of the RF magnetron sputtered coatings even when the average power input was two times higher. However, it has been shown that the RF coatings require heating the substrate above 400 °C to obtain a crystalline structure, while the HiPIMS method allows for a reduction of the substrate temperature to 300 °C.

Keywords:
RF magnetron sputtering, HiPIMS magnetron sputtering, Superhard ceramic coatings, Transition metal borides, Deposition temperature

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

Dąbrowski M., Brachaczek A., Bogusz K., Glinicki M.A., Experimental assessment of appropriate time for aggregate exposure at the surface of cement concrete pavement, International Journal of Pavement Engineering, ISSN: 1029-8436, DOI: 10.1080/10298436.2024.2318607, Vol.25, No.1, pp.1-12, 2024

Abstract:
Exposed aggregate concrete (EAC) pavement is a commonly employed technology in Europe for the construction of highways. The technical challenges associated with pavement construction include achieving both a comfortable ride and the desired skid resistance, while ensuring the long-term concrete durability. Maintaining uniformity of concrete mix, precise dosing of retarding agents, optimal selection of brushing time, and ensuring adequate curing conditions are identified as critical factors for achieving the designed ride performance. This study is focused on determining the appropriate time for the brushing operation, conducted to expose aggregate grains at the surface of the pavement. Laboratory tests were performed on concrete mixes designed to replicate job mixes for the upper layer of a two-layer concrete pavement. Measurements of the mass of evaporated water from the cement paste, isothermal calorimetry tests, and modified Vicat tests were employed to predict the appropriate brushing time. The texture depth was determined using a laser profiler as a function of brushing time. Compressive strength, the rate of chloride ion migration, and scaling resistance were determined through tests conducted on specimens cut from exposed aggregate slabs. Results revealed the suitability of the developed test method for determining the appropriate time for brushing EAC pavements.

Keywords:
cement setting, exposed aggregate concrete, macrotexture, pavement durability, surface retarder, texturing technology

Kopeć M., Gunputh U., Williams G., Macek W., Kowalewski Z.L., Wood P., Fatigue Damage Evolution in SS316L Produced by Powder Bed Fusion in Different Orientations with Reused Powder Feedstock, EXPERIMENTAL MECHANICS, ISSN: 0014-4851, DOI: 10.1007/s11340-024-01118-1, pp.1-16, 2024

Abstract:
Background

Metal Laser Powder Bed Fusion Melting (LPBF-M) is considered economically viable and environmentally sustainable because of the possibility of reusing the residual powder feedstock leftover in the build chamber after a part build is completed. There is however limited information on the fatigue damage development of LPBF-M samples made from reused feedstock.
Objective

In this paper, the stainless steel 316 L (SS316L) powder feedstock was examined and characterised after 25 reuses, following which the fatigue damage development of material samples made from the reused powder was assessed.
Methods

The suitability of the powder to LPBF-M technology was evaluated by microstructural observations and measurements of Hall flow, apparent and tapped density as well as Carr’s Index and Hausner ratio. LPBF-M bar samples in three build orientations (Z – vertical, XY – horizontal, ZX – 45° from the build plate) were built for fatigue testing. They were then subjected to fatigue testing under load control using full tension and compression cyclic loading and stress asymmetry coefficient equal to -1 in the range of stress amplitude from ± 300 MPa to ± 500 MPa.
Results

Samples made from reused powder (25 times) in the LPBF-M process exhibited similar fatigue performance to fresh unused powder although a lower ductility for vertical samples was observed during tensile testing. Printing in horizontal (XY) and diagonal (ZX) directions, with reused powder, improved the service life of the SS316L alloy in comparison to the vertical (Z).
Conclusions

Over the 25 reuses of the powder feedstock there was no measurable difference in the flowability between the fresh (Hall Flow: 21.4 s/50 g) and reused powder (Hall Flow: 20.6 s/50 g). This confirms a uniform and stable powder feeding process during LPBF-M for both fresh and reused powder. The analysis of fatigue damage parameter, D, concluded cyclic plasticity and ratcheting to be the main mechanism of damage.

Keywords:
SS316L ,Stainless steel,Fatigue ,Additive manufacturing,Laser Powder Bed Fusion Melting (LPBF-M)

Kopeć M., Gunputh U., Macek W., Kowalewski Z.L., Wood P., Orientation effects on the fracture behaviour of additively manufactured stainless steel 316L subjected to high cyclic fatigue, Theoretical and Applied Fracture Mechanics, ISSN: 0167-8442, DOI: 10.1016/j.tafmec.2024.104287, pp.1-20, 2024

Abstract:
In this paper, stainless steel 316L (SS316L) bars were additively manufactured (AM) in three orientations (Z – vertical, XY – horizontal, ZX45 – midway between vertical and horizontal) by using the Laser Powder Bed Fusion Melting (LPBF-M) method. The AM specimens were subjected to load control fatigue testing under full tension and compression (R = -1) at stress amplitudes ±350, ±400 and ±450 MPa. The XY and ZX45 printing orientations were found to significantly improve service life. Although similar strain response was found for each orientation when the same stress amplitude was applied, slightly different fracture mechanisms were identified during the post-mortem surface observations.

Keywords:
SS316L,stainless steel,fatigue,additive manufacturing,Laser Powder Bed Fusion Melting (LPBF-M)

Lisowski P., Glinicki M.A., Novel Processing Methods of Low-Clinker Multi-Component Cementitious Materials—A Review, Applied Sciences, ISSN: 2076-3417, DOI: 10.3390/app14020899, Vol.14(2), No.899, pp.1-28, 2024

Abstract:
The wide use of multi-component cement of highly reduced Portland clinker factor is largely impeded by detrimental changes in the rheological properties of concrete mixes, a substantial reduction in the early rate of cement hardening, and sometimes the insufficient strength of mature concrete. Therefore, major changes are needed in traditional concrete-production technologies if low-clinker cement is to gain wider acceptance. This review’s goal is to summarize the impacts of using non-ionizing radiation methods to improve the dispersion of concrete mix constituents, cement setting, and early hardening. The potential impacts of such interactions on the permeability and strength of concrete are also highlighted and investigated. Their intriguing potential for delivering additional energy to cementitious mixtures is analyzed for batch water, solid non-clinker constituents of cement (mainly supplementary cementitious materials), and their mixtures with aggregates. The advantages of adopting these non-traditional methods are found to be highly alluring to the greener preparation techniques used in the construction materials sector.

Keywords:
concrete mixing technology,early-age properties,low-clinker multi-component cement,magnetized water,microwave treatment,non-clinker constituents,ultrasound treatment

Kopeć M., Mierzejewska I., Gorniewicz D., Sitek R., Jóźwiak S., High-temperature oxidation behaviour of additively manufactured and wrought HAYNES 282, JOURNAL OF MATERIALS SCIENCE, ISSN: 0022-2461, DOI: 10.1007/s10853-024-10207-4, pp.1-19, 2024

Abstract:
Direct Metal Laser Sintered Haynes 282 specimens as well as wrought ones were subjected to high-temperature exposure at 1000 °C for 100h in air to compare their oxidation behaviour. The specimens were removed from the furnace after 1h, 5h, 25h, 50h and 100h to reveal and study oxidation mechanisms through morphological and cross-sectional examination by using scanning electron microscopy with energy dispersive spectroscopy attachment and X-ray diffraction. Microstructural studies revealed that the oxidation kinetics, determined by changes in thickness scale and depth of aluminium diffusion zone, were mainly driven by the formation of Cr2O3 for the wrought material, and TiO2 for DMLS one. The wrought material was characterized by the oxidation rate equal to 0.96 and followed the logarithmic law. On the other hand, DMLS-manufactured Haynes 282 exhibited oxidation rate of 0.90 and follows the linear law for the thickness scale considerations. However, when the depth of aluminium diffusion was investigated, it had an oxidation rate of 0.87 and followed cubic law.

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

Makowska K., Kowalewski Z.L., Analysis of the Microstructure and Hardness of Flake Graphite Cast Iron Using the Barkhausen Noise Method and Conventional Techniques, JOURNAL OF NONDESTRUCTIVE EVALUATION, ISSN: 0195-9298, DOI: 10.1007/s10921-024-01065-w, Vol.43, No.54, pp.1-12, 2024

Abstract:
The new brake disc was evaluated for microstructure and hardness by the conventional destructive tests and non-destructive Barkhausen noise method (BNM). Ten non-destructive measurements were carried out in different areas of a brake disc, which were then cut out and made into metallographic test samples. Qualitative and quantitative analysis of graphite precipitates was performed to assess their volume in material matrix, anisotropy and size. Subsequently, graphs showing the relationships between selected stereological parameters of graphite precipitates and parameters determined from the RMS envelope of Barkhausen noise were elucidated. Similar relationships between hardness and parameters coming from non-destructive tests were carried out. Magnetic parameters that specified the size of a graphite precipitate was selected. In addition, repeatability studies using BNM were carried out in the areas of the material with the smallest and largest average size of graphite precipitates. A linear relationship between amplitude of BN and length of graphite flakes was found. The paper presents the possibilities of assessing the volume and size of graphite precipitates, as well as cast iron hardness using BNM.

Keywords:
Flake cast iron,Barkhausen noise,Brake disc,Non-destructive testing,Hardness

Tytko G., Adamczyk-Habrajska M., Luo Y., Kopeć M., Eddy Current Testing in the Quantitive Assessment of Degradation State in MAR247 Nickel Superalloy with Aluminide Coatings, JOURNAL OF NONDESTRUCTIVE EVALUATION, ISSN: 0195-9298, DOI: 10.1007/s10921-024-01129-x, Vol.43, No.112, pp.1-10, 2024

Abstract:
In this paper, the effectiveness of the eddy current methodology for crack detection in MAR 247 nickel-based superalloy with aluminide coatings subjected to cyclic loading was investigated. The specimens were subjected to force-controlled fatigue tests under zero mean level, constant stress amplitude from 300 MPa to 600 MPa and a frequency of 20 Hz. During the fatigue, a particular level of damage was introduced into the material leading to the formation of microcracks. Subsequently, a new design of probe with a pot core was developed to limit magnetic flux leakage and directed it towards the surface under examination. The suitability of the new methodology was further confirmed as the specimens containing defects were successfully identified. The changes in probe resistance values registered for damaged specimens ranged approximately from 8 to 14%.

Keywords:
Nickel alloys, Aluminide coating, Non-destructive testing, Eddy current testing

Haponova O., Tarelnyk V., Mościcki T. P., Tarelnyk N., Półrolniczak J., Myslyvchenko O., Adamczyk-Cieślak B., Sulej-Chojnacka J., Investigation of the Structure and Properties of MoS2 Coatings Obtained by Electrospark Alloying, Coatings, ISSN: 2079-6412, DOI: 10.3390/coatings14050563, Vol.14, No.563, pp.1-15, 2024

Abstract:
Electrospark coatings alloyed with MoS2 have been studied. The coatings were obtained by the following two strategies: the first consisted of pre-applying molybdenum disulfide to the treated surface and alloying with a molybdenum electrode (Mo + MoS2 coating); the second consisted of applying a paste with a sulfur content of 33.3% to the treated surface and alloying with a molybdenum electrode (Mo + S coating). The structure, phase composition, and tribological properties of the coatings were investigated. The coatings have a complex structure consisting of an upper soft layer, a hardened white layer, a diffusion zone, and a substrate. Element analysis and cross-sectional hardness changes indicated that element diffusion occurred at the coating/substrate interface. The phase composition of the coatings is represented by BCC and FCC solid solutions on Fe, and MoS2 is also detected. In Mo + S coatings, the molybdenum disulfide on the surface is about 8%; in Mo + MoS2 coatings, it is 27%–46%. The obtained coatings show very good tribological properties compared to molybdenum ESA coatings. The frictional forces and coefficients are reduced by a factor of 10 and 40, depending on the test conditions.

Keywords:
electrospark alloying, coating, structure, molybdenum disulfide, tribological properties, energy conservation

Kopeć M., Recent Advances in the Deposition of Aluminide Coatings on Nickel-Based Superalloys: A Synthetic Review (2019–2023), Coatings, ISSN: 2079-6412, DOI: 10.3390/coatings14050630, Vol.14, No.630, pp.1-15, 2024

Abstract:
Thermal barrier coatings (TBCs) are widely used to improve the oxidation resistance and high-temperature performance of nickel-based superalloys operating in aggressive environments. Among the TBCs, aluminide coatings (ACs) are commonly utilized to protect the structural parts of jet engines against high-temperature oxidation and corrosion. They can be deposited by differ-ent techniques, including pack cementation (PC), slurry aluminizing or chemical vapor deposition (CVD). Although the mentioned deposition techniques have been known for years, the constant developments in materials sciences and processing stimulates progress in terms of ACs. There-fore, this review paper aims to summarize recent advances in the AC field that have been report-ed between 2019 and 2023. The review focuses on recent advances involving improved corrosion resistance in salty environments as well as against high temperatures ranging between 1000 °C and 1200 °C under both continuous isothermal high-temperature exposure for up to 1000 h and cyclic oxidation resulting from AC application. Additionally, the beneficial effects of enhanced mechanical properties, including hardness, fatigue performance and wear, are discussed.

Keywords:
high-temperature corrosion, aggressive environment, coating deposition

Kopeć M., Effect of Aluminide Coating Thickness on High-Temperature Fatigue Response of MAR-M247 Nickel-Based Superalloy, Coatings, ISSN: 2079-6412, DOI: 10.3390/coatings14081072, Vol.14(8), No.1072, pp.1-12, 2024

Abstract:
In this paper, 20 µm and 40 µm thick aluminide coatings were deposited on MAR-M247 nickel-based superalloy through the chemical vapor deposition (CVD) process in a hydrogen protective atmosphere for 4 h and 12 h, respectively, at a temperature of 1040 °C and an internal pressure of 150 mbar. The effect of aluminide coating thickness on the high-temperature performance of the MAR-M247 nickel-based superalloy was examined during a fatigue test at 900 °C. After high-temperature testing, the specimens were subjected to fractographic analysis to reveal the damage mechanisms. No significant effect of coating thickness was found since the material exhibited a similar service life throughout the fatigue test when subjected to the same stress amplitude. One should stress that the coating remained well adhered after specimen fracture, confirming its effectiveness in protecting the material against high-temperature oxidation.

Keywords:
fatigue, aluminide coatings, nickel alloys , high-temperature performance

Jóźwiak-Niedźwiedzka D., Choinska C., Brachaczek A., Dąbrowski M., Ośko J., Kuć M., Gas permeability and gamma ray shielding properties of concrete for nuclear applications, NUCLEAR ENGINEERING AND DESIGN, ISSN: 0029-5493, DOI: 10.1016/j.nucengdes.2024.113616, Vol.429, No.113616, pp.1-14, 2024

Abstract:
Concrete used in nuclear applications faces significant durability challenges due to degradation from radiation, thermal stresses, and chemical reactions. These issues highlight the critical need for impermeable concrete shields to prevent radioactive leaks and protect against harmful radiation. This study examines how concrete composition affects gas permeability and gamma radiation shielding properties. Three coarse aggregates—amphibolite (reference), magnetite, and serpentine—and two cement types (ordinary and slag) were tested, with concrete densities ranging from 2309 to 3538 kg/m3. Gas permeability was measured using a Cembureau-type constant head permeameter, and gamma shielding was assessed through the linear attenuation coefficient (µ) and half-value layer (HVL) at 137Cs decay energies. The results revealed significant variations in gas permeability and gamma ray shielding based on aggregate and cement type, with observable relationships between gas permeability, HVL, and concrete density. The results obtained from the presented research will contribute to increasing the safety, durability and cost-effectiveness of concrete constructions and maintenance of nuclear facilities.

Keywords:
Heavyweight aggregate, Hydrogen-bearing aggregate, Shielding concrete, Gas permeability, Gamma ray attenuation, Microstructure, ITZ

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

Makowska K., Szymczak T., Kowalewski Z.L., Fatigue Behaviour of Medium Carbon Steel Assessed by the Barkhausen Noise Method, ACTA MECHANICA ET AUTOMATICA, ISSN: 1898-4088, DOI: 10.2478/ama-2024-0005, Vol.18, No.1, pp.40-47, 2024

Abstract:
In this paper, an attempt to estimate the stage of the fatigue process using the Barkhausen noise method is studied. First, microstructural and static tensile tests were carried out and, subsequently, fatigue tests up to failure were conducted. After determination of the material behaviour in the assumed static and dynamic conditions, the interrupted fatigue tests were performed. Each specimen was stressed up to a different number of cycles corresponding to 10%, 30%, 50%, 70% and 90% of fatigue lifetime for the loading conditions considered. In the next step of the experimental programme, the specimens were subjected to the Barkhausen magnetic noise measurements. Various magnetic parameters coming from the rms Barkhausen noise envelopes were determined. The linear relationship betweenthe full-width at half-maximum (FWHM) of the Barkhausen noise envelope and the number of loading cycles to fracture was found. Specimens loaded up to a certain number of cycles were also subjected to a tensile test to assess an influence of fatigue on the fracture features

Keywords:
fatigue, Barkhausen noise, structural steel, fracture, mechanical properties, deformation

Mackiewicz S., Ranachowski Z., Katz T., Dębowski T., Starzyński G., Ranachowski P., Modeling of Acoustic Coupling of Ultrasonic Probes for High-Speed Rail Track Inspection, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2024.148787, pp.1-12, 2024

Abstract:
The paper presents the modeling of transmission of the ultrasonic plane wave through an uniform liquid layer. The considered sources of the ultrasonic wave were normal (straight) beam longitudinal wave probes and angle beam sheer waves probes commonly used in non-destructive testing. Coupling losses (CL) introduced by the presence of the coupling layer are discussed and determined applying the numerical procedure. The modeling applies to both monochromatic waves and short ultrasonic pulses with a specified frequency bandwidth. Model implementation and validation was performed using a specialized software. The predictions of the model were confirmed by coupling losses measurements for a normal beam longitudinal wave probe with a delay line made of polymethyl methacrylate (PMMA). The developed model can be useful in designing ultrasonic probes for high-speed rail track inspections, especially for establishing the optimal thickness of the water coupling layer and estimation of coupling losses, due to inevitable changes of the water gap during mobile rail inspection.

Keywords:
non-destructive testing, ultrasonic examination, plane wave propagation

Haponova O., Tarelnyk V., Mościcki T. P., Tarelnyk N., Investigating the effect of electrospark alloying parameters on structure formation of modified nitrogen coatings, BULLETIN OF THE POLISH ACADEMY OF SCIENCES: TECHNICAL SCIENCES, ISSN: 0239-7528, DOI: 10.24425/bpasts.2024.150802, Vol.72, No.5, pp.1-8, 2024

Abstract:
The quality parameters of surface layers synthesised using electrospark alloying (ESA) technology were analysed in this paper. The main focus was on the influence of equipment energy parameters on structure formation, specifically the effect of discharge energy and productivity. Microstructural analysis of the modified surface of C40 steel after nitriding by ESA using a paste containing nitrogen compounds injected into the interelectrode gap was conducted. The layer structure for all studied ESA parameters includes three areas: the upper “white layer”, the diffusion zone below it, and the substrate. The roughness of the surface is Ra ∼ 0.9 μm at low discharge energy Wp = 0.13 J and Ra ∼ 6 μm at Wp = 3.4 J. The microhardness, continuity, and surface roughness of the layers varied with Wp. The influence of ESA productivity on the structure was studied. The thickness of the hardened layer and the diffusion zone, as well as the microhardness and continuity, are affected by reduced productivity. For the same discharge energy, the thickness of the hardened layer increases by 10-18% with a decrease in productivity compared to the classical mode.

Keywords:
electrospark alloying, discharge energy, productivity, coating, structure

Tabin J., Brodecki A., Parametrisation of Uniform Deformation in Ductile Metals Using Digital Image Correlation Technology, EXPERIMENTAL TECHNIQUES, ISSN: 0732-8818, DOI: 10.1007/s40799-024-00704-1, pp.1-12, 2024

Abstract:
This paper presents a novel measurement method that aims to qualitatively and quantitatively assess uniform deformation during displacement- and force-controlled tensile tests of ductile metals. The method utilizes digital image correlation technology to record the strain distribution during tensile testing, followed by the calculation of the floating root mean square (RMS) value of the strain amplitude along the specimen axis. By implementing this approach, the RMS-based profiles of strain amplitude are identified in different metals and alloys, including austenitic stainless steels, structural steel, copper, and aluminium alloys. Moreover, the proposed method holds potential for predicting important deformation characteristics such as distribution of intensive plastic zones, necking effect, and delocalization effect. Thus, it establishes a link between macroscale and microscale during the analysis of plastic deformation behaviour. The effectiveness of the new method is compared with existing strain and strain-rate methods. The novel approach demonstrates promising advantages in the context of the identification of metal-forming parameters.

Keywords:
Digital image correlation, Root mean square, Uniform strain distribution, Strain delocalization, Necking effect

Glinicki M. A., Jóźwiak-Niedźwiedzka D., Brandt A., Diagnostics of premature damage to surface-hardened industrial concrete floors, CEMENT, WAPNO, BETON, ISSN: 1425-8129, DOI: 10.32047/CWB.2023.28.6.4, Vol.28, No.6, pp.409-427, 2024

Abstract:
The article presents the diagnostic results on surface-hardened industrial concrete floors. Selected examples of floors showcased premature damage to surface layers, characterized by intense dusting, delamination, and local spalling, while the structural system remained unaffected. Quantitative petrographic analysis of concrete was applied to core specimens from the floors, involving the examination of digital images from a polarizing optical microscope and a scanning electron microscope. The hardening compound and powdered specimens of the cement matrix were characterized using differential thermal analysis and X-ray diffraction. A multiple microindentation method was employed to assess local variations in mechanical properties. Concrete cross-section analysis revealed areas with a non-uniform distribution of air voids, identified regions exhibiting increased porosity, highlighted areas of cracking in the concrete, indicated local variability in the phase composition of cement hydration products, and pointed out the presence of carbonated areas. The causes of the damage were discussed based on these findings,. The crucial role of quantitative petrographic analysis in diagnosing premature surface damage to industrial floors was demonstrated.

Keywords:
concrete, delamination, quantitative microscopy, porosity, industrial floors, dusting, surface hardening

Makowska K., Kowalewski Z.L., Evaluation of microstructure and mechanical properties of ferromagnetic structural steels using Barkhausen noise, JOURNAL OF THEORETICAL AND APPLIED MECHANICS, ISSN: 1429-2955, DOI: 10.15632/jtam-pl/191444, Vol.62, No.3, pp.587-599, 2024

Abstract:
The paper presents an attempt to assess the microstructure and mechanical properties by means of the magnetic Barkhausen noise (MBN) method. The experimental program was supplemented by metallographic examinations and hardness tests. It has been concluded that the MBN method can be used for non-destructive characterization of both single and two-phase steels used in the automotive industry. It was also found that the microstructure of steel can be distinguished using the shape of BN envelope and two magnetic parameters: Ubpp1 and Ug1. On the other hand, the hardness and ultimate tensile strength are described successfully by the Ug1/Ubpp1 parameter.

Keywords:
microstructure, mechanical properties, Barkhausen noise, non-destructive method

Haponova O.^♦, Tarelnyk V., Zhylenko T., Tarelnyk N., Vasilenko O., Pavlovskyi S., Improvement of the Quality Parameters of the Surface Layers of Steel Parts after Aluminizing by Electrospark Alloying. Pt. 2. Results of the Influence of the Productivity of Aluminizing by Electrospark Alloying on the Structural State of Steel Surfaces, Metallofizika i Noveishie Tekhnologii, ISSN: 1024-1809, DOI: 10.15407/mfint.46.04.0313, Vol.46, No.4, pp.313-324, 2024

Abstract:
In the article, investigation is carried out at the second stage of aluminizing, when a consistent substance containing aluminium powder (the first option) or graphite powder and aluminium powder (the second option) is applied to the surface that has undergone aluminizing at the first stage, before further electrospark alloying with an aluminium electrode, and, regardless of the drying of the consistent substance, the aluminizing process is carried out at a discharge energy of 0.52–2.6 J and a productivity of 1.0–2.0 cm2/min, while the discharge energy and productivity are chosen such that the surface roughness decreases by ≅ 3–4 times. At the second stage aluminizing for both options, when using a consistent substance that contains aluminium powder or aluminium powder and graphite powder, the microhardness of the ‘white layer’ and the diffusion zone are increased (to a greater degree when graphite is present in the consistent substance), the surface roughness is decreased, and the integrity of the coating is of 100%. Before practical implementation, it is recommended to carry out the aluminizing process according to the first option at the discharge energy Wp = 4.6–6.8 J, using a consistent substance containing aluminium powder and graphite powder at the second stage.

Keywords:
electrospark alloying,aluminizing,productivity,surface layer,quality,structure,roughness,microhardness,thickness of the white layer,coating continuity

Kopeć M., Kukla D., Wyszkowski M., Kowalewski Z.L., High temperature fatigue testing of turbine blades, FATIGUE OF AIRCRAFT STRUCTURES, ISSN: 2300-7591, DOI: 10.2478/fas-2023-0002, Vol.15, pp.22-27, 2024

Abstract:
This paper evaluates the efficacy of a patented grip for high-temperature fatigue testing by establishing the S-N curve for full-scale nickel-based turbine blades under simulated environmental conditions. Initially, a bending test assessed the stress-displacement characteristics of the component. This was followed by a series of fatigue tests at 950°C, using cyclic bending with force amplitudes from 5.2 kN to 6.6 kN and a constant frequency of 10 Hz. The setup, integrating the grip into a standard testing machine,
proved effective for high-temperature tests and successfully determined the service life of full-scale components.

Keywords:
fatigue,high temperature,turbine blade,full-scale fatigue test

Glinicki M. A., Jóźwiak-Niedźwiedzka D., Brandt A., Dziedzic K., Ilościowa charakterystyka mikrostruktury betonu w diagnostyce powierzchniowych uszkodzeń posadzki przemysłowej / Quantitative assessment of concrete microstructure in tlie diagnosis of surface damage to industrial floor, INŻYNIERIA I BUDOWNICTWO, ISSN: 0021-0315, DOI: 10.5604/01.3001.0054.7476, Vol.80, No.6, pp.400-404, 2024

Abstract:
Przedstawiono wyniki oceny diagnostycznej posadzki przemysłowej przy wykorzystaniu metodyki ilościowej oceny mikrostruktury betonu. Objawy uszkodzeń obejmowały pylenie powierzchniowe i delaminację warstwy utwardzonej. Przeprowadzono analizę petrograficzną składu betonu w próbkach-odwiertach. Zaobserwowano nadmierne napowietrzenie betonu, gromadzenie się porów powietrznych i występowanie ukierunkowanych spękań, miejscową zmienność składu fazowego produktów hydratacji cementu, w tym występowanie obszarów o intensywnej karbonatyzacji, co wpływało na przedwczesne uszkodzenia powierzchniowe.
Diagnostic assessment of industrial floor using the methodology of quantitative evaluation of concrete microstructure is presented. Symptoms of damage included surface dusting and delamination of the top layer. A petrographic analysis of the concrete composition in core specimens was carried out. Excessive air content, accumulation of air voids and the occurrence of oriented cracks, local variability of the phase composition of cement hydration products, including the occurrence of carbonated areas were observed and associated with the premature surface damage.

Keywords:
delaminacja, mikroskopia ilościowa, porowatość, posadzki betonowe, utwardzenie powierzchniowe, delamination, quantitative microscopy, porosity, concrete floors, surface hardening