Instytut Podstawowych Problemów Techniki

Rogala M., Ferdynus M., Kopeć M., The effect of multilevel spherical triggers on the crashworthiness capacity of thin-walled structures, Aerospace Science and Technology, ISSN: 1270-9638, DOI: 10.1016/j.ast.2025.110299, Vol.163, No.110299, pp.1-18, 2025

Abstract:
Progressive dynamic crushing remains a significant focus in contemporary research aimed at developing and optimizing energy-absorbing structures. This study investigates thin-walled passive energy absorbers featuring multi-level crush initiators in the form of spherical embossments. The experimental setup involved aluminum columns subjected to an impact energy of 1700 J. These columns were designed with varying numbers of embossment levels. Key parameters of the spherical embossments included diameters ranging from 12 to 36 mm and depths from 1.2 to 4.8 mm. Dynamic impact tests were conducted using an Instron Ceast 9350 HES drop tower, with deformation behavior captured via a Phantom Miro M310 high-speed camera. Complementary finite element analyses were also performed to obtain force-displacement responses and crushing efficiency indicators, enabling a comparative assessment of structural performance based on different crush initiator configurations. The results demonstrate that spherical embossments enhance the stability of the crushing process by reducing the peak crushing force. Furthermore, incorporating additional embossment levels increases the mean crushing force and improves the overall energy absorption efficiency of the passive energy absorber.

Keywords:
Multi-level trigger , Spherical embossment, Crashworthiness

Tytko G., Adamczyk-Habrajska M., Linke Y., Liu Z., Kopeć M., High frequency eddy current method in inspection of aluminide coatings integrity after simulating service loads, MEASUREMENT, ISSN: 0263-2241, DOI: 10.1016/j.measurement.2025.117356, Vol.252, No.117356, pp.1-11, 2025

Abstract:
This study investigates the use of high-frequency eddy current testing (ECT) to assess the structural integrity of aluminide coatings on MAR-M247 nickel superalloy under simulated fatigue conditions. Aluminide coatings, deposited via chemical vapor deposition at thicknesses of 20 µm and 40 µm, were tested using custom-designed probes optimized for defect detection. Results demonstrate that substrate grain structure and coating thickness significantly influence coating durability, with fine-grain substrates exhibiting the least resistance changes and greatest fatigue tolerance. Eddy current signal variations correlated with microstructural changes, enabling detection of damage otherwise invisible to traditional methods. These findings establish ECT as a precise, non-destructive approach for monitoring aluminide coatings in critical applications.

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

Haponova O., Tarelnyk V., Tarelnyk N., Laponog G., Investigation of Aluminum Electrospark Alloyed Coatings on Steels, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-025-07908-z, Vol.56, pp.4204-4229, 2025

Abstract:
The paper presents a study of the structure-phase state of aluminised coatings obtained by the electrospark alloying (ESA) method. The influence of the discharge energy and the productivity of the treatment process on the thickness of the hardened layer, its microhardness, continuity and surface roughness of C20 and C40 steels has been studied. It is shown that the structure of ESA coatings consists of a white layer, a diffusion zone and a substrate metal. Increasing the discharge energy during ESA leads to a change in the chemical and phase composition of the layer. With a 2-fold decrease in ESA productivity, the thickness of the “white” layer increases to 75 to 110 µm, its microhardness to 7450 MPa; the continuity of the coating tends to 100 pct. With a 4-fold decrease in ESA productivity, the thickness of the ‘white’ layer also increases, but not intensively, to 60 µm at Wp = 4.6 J and then does not change; at the same time, the surface roughness Ra increases to 8.1 to 9.0 µm and the continuity is 95 pct. A 4-fold decrease in process productivity contributes to the deterioration of coating quality parameters and an increase in roughness. The study of the influence of the energy parameters of ESA, as well as the alloying time (‘productivity’) of the process, is important for the improvement of hardening technology. The paper proposes a mathematical model for predicting the coating parameters taking into account the processing time of a given plane to be alloyed, i.e., the labour intensity of the ESA process (the value of the inverse productivity). The equations of the mathematical model and methods for determining the constants of the equations for predicting the parameters of the alloyed layer have been obtained. An algorithm has been developed and the adequacy of the mathematical model has been verified, which allows the prediction of the main technological parameters of ESA in order to obtain a coating with the specified quality indicators.

Widomski P., Kaszuba M., Barełkowski A., Smolik J., Garbiec D., Ciemiorek-Bartkowska M., Kulikowski K., Lewandowska-Szumieł M., Mościcki T., Gronostajski Z., WTaB coatings as effective solutions for increasing die durability in lead-free brass alloy flashless hot forging process, WEAR, ISSN: 0043-1648, DOI: 10.1016/j.wear.2025.205849, Vol.571, No.205849, pp.1-10, 2025

Abstract:
The forging of lead-free brass alloys is characterized by low tool durability, presenting a significant challenge in industrial applications. To address this issue, unique magnetron-sputtered coatings based on WB and with the addition of Tantalum, were employed to increase tool life. These coatings were produced from proprietary sintered targets using the SPS-HiPIMS technology. Initially, the coatings underwent laboratory testing, where their microstructure, adhesion to the substrate, and mechanical properties were tested and evaluated. The next phase involved testing these coatings on tools used in hot flashless forging processes. The experiments were conducted on dies that were preliminarily gas-nitrided to provide a suitable substrate for the coating application. The results were compared with those of only nitrided dies.
The study involved the use of nitrided dies, dies with WB2.5 and with W0.76Ta0.24B2.5 coatings. After forging, the tools were observed to assess the wear mechanisms. Surface scans were performed to measure material loss by comparing the surface profiles before and after forging. Scanning Electron Microscopy (SEM) was used to analyze the contribution of various wear mechanisms, such as abrasive wear, thermo-mechanical fatigue, and plastic deformation, to the overall tool wear.
The results confirmed the beneficial impact of these coatings on enhancing tool durability. In certain cases, the service life of the tools was extended by up to 50 %. This study demonstrates that the application of newly developed W0.76Ta0.24B2.5 coating which can significantly improve the durability of tools used in the flashless forging of lead-free brass alloys, offering a promising solution for industrial manufacturing challenges.

Łazarska M., Ranachowski Z., Musiał J., Tański T., Jiang Q., Identification of Phase Transformations in Alloy and Non-Alloy Steel During Austempering Using Acoustic Emission and Neural Network, Materials, ISSN: 1996-1944, DOI: 10.3390/ma18102198, Vol.18, No.2198, pp.1-16, 2025

Abstract:
This research was carried out for selected alloy (bearing) and non-alloy (tool) steel. The steels were subjected to austempering. The hardening temperature range was from 100 °C to 180 °C. The use of acoustic emission in connection with the artificial neural network (ANN) enabled the analysis and identification of phase changes occurring in steels during austempering. Classification of acoustic emission events was carried out with the help of their energy values and with the use of an artificial neural network. On this basis, it was observed that in the process of isothermal hardening of steel at the applied temperatures, complex transformations of austenite into martensite and bainite occur. In addition, it was found that the research methods used enabled the identification of signal components originating from the phase transformation causing the formation of thin-plate martensite midrib. The use of acoustic methods in the field of bainitic transformation creates the possibility of their application in the industry.

Keywords:
bainite, martensite, austempering, acoustic emission (AE), neural networks

Macek W., Sitek R., Podulka P., Lesiuk G., Zhu S., Liu X., Kopeć M., Fractography of Haynes 282 alloy manufactured by DMLS after tensile and HCF, Journal of Constructional Steel Research, ISSN: 1873-5983, DOI: 10.1016/j.jcsr.2025.109623, Vol.232, No.109623, pp.1-12, 2025

Abstract:
In this paper, the fracture surface topography of additively manufactured Haynes 282 alloy subjected to tensile and high-cycle fatigue loading was investigated. Haynes 282 alloy bars were printed in three different directions relative to the base plate (0°, 45°, and 90°) via Direct Metal Laser Sintering (DMLS) under an argon protective atmosphere. The specimens were subjected to monotonic tensile loading and fatigue testing under load control using full tension and compression cyclic loading (R = −1) in the range of stress amplitude from ±550 MPa to ±800 MPa. The entire surface topography was evaluated by using a 3D non-contact confocal technique and post-failure specimens after a fatigue test performed at three stress amplitudes, ±650 MPa, ±700 MPa and ±750 MPa. Such an attempt was proposed to analyse the fatigue response of AM Haynes 282 in the region near its yield strength. It was found that the printing orientation and the stress amplitude have a strong impact on service life and fracture surface characteristics. Finally, a surface topography parameter involving the mass density of furrows, root-mean-square height, and fractal dimension was successfully combined with the stress amplitude to estimate the fatigue life. The findings offer a novel approach to fatigue life prediction based on post-failure surface analysis, providing valuable insights for industrial applications and forensic engineering.

Keywords:
Nickel alloys,Fatigue,Additive manufacturing,Direct Metal Laser Sintering (DMLS),Fracture,Surface topography

Kopeć M., Przygucka D., Sitek R., Jóźwiak S., Orientation-dependent low-cycle fatigue and grain boundary evolution in DMLS-fabricated Haynes 282 superalloy, Manufacturing Letters, ISSN: 2213-8463, DOI: 10.1016/j.mfglet.2025.06.206, Vol.45, pp.1-8, 2025

Abstract:
This study investigates the effect of build orientation on the fatigue performance of Haynes 282 alloy manufactured via Direct Metal Laser Sintering at 0°, 45°, and 90°. Fatigue tests revealed superior service life for 0° and 45° orientations, attributed to equiaxed grains and high-angle grain boundaries identified by EBSD. Vertical builds exhibited columnar grains and reduced fatigue resistance. This work provides the first systematic correlation between grain boundary character and low-cycle fatigue behavior in DMLS-manufactured Haynes 282, expanding current understanding beyond Inconel-based systems and offering insights for orientation-based design optimization in critical high-temperature applications

Keywords:
Nickel alloys, Fatigue, Additive manufacturing, Direct metal laser sintering (DMLS)

Brachaczek A., Tokpatayeva R., Olek J., Jarząbek D.M., Piotrowski P., Jenczyk P., Jóźwiak-Niedźwiedzka D., Impact of formate based deicing agents on ASR products: Microstructural, chemical and mechanical characteristics, CONSTRUCTION AND BUILDING MATERIALS, ISSN: 0950-0618, DOI: 10.1016/j.conbuildmat.2025.140729, Vol.471, No.140729, pp.1-12, 2025

Abstract:
This study investigates the effects of formate-based deicing agents, specifically potassium formate (HCOOK) and sodium formate (HCOONa), on alkali-silica reaction (ASR) in concrete. By adapting ASTM C1260 standards, mortar bars were subjected to deicing solutions of varying concentrations to evaluate their influence on mortar expansion and ASR product characteristics. Results revealed that high concentrations of formate solutions significantly accelerated ASR, inducing expansions comparable to or greater than those caused by sodium hydroxide, while sodium chloride showed minimal expansion effects. Microstructural and chemical analyses demonstrated that ASR gels formed in formate solutions were predominantly amorphous, with different chemical composition depending on the deicer type. Pore solution analysis indicated a strong correlation between alkali ion concentration and mortar expansion. Furthermore, mechanical testing of ASR products revealed that gels formed in potassium formate exhibited higher hardness and elastic modulus compared to those formed in sodium formate. These findings enhance understanding of the detrimental effects of formate-based deicing agents on ASR and provide a foundation for developing mitigation strategies to preserve concrete infrastructure.

Keywords:
Alkali-silica reaction,Concrete microstructure,Expansion,Nanoindentation,Deicing agents,Pore solution analysis

Brachaczek A., Dąbrowski M., Lisowski P., Dziedzic K., Glinicki M.A., Alkali threshold level in concrete to trigger the alkali-silica reaction at simulated road pavement environments with alkali supply, CONSTRUCTION AND BUILDING MATERIALS, ISSN: 0950-0618, DOI: 10.1016/j.conbuildmat.2025.142023, Vol.487, No.142023, pp.1-17, 2025

Abstract:
To minimize the potential risk of concrete damage due to alkali-silica reaction (ASR) when using ordinary Portland cement in concrete mixtures, the alkali threshold level must be established for specific aggregate combinations. Since deicing salts used in the winter maintenance of highway structures can serve as an external source of alkalis, their impact on alkali threshold determination should be evaluated. An experimental investigation was conducted on concrete specimens subjected to a 60°C performance test, both with and without an external alkali supply. Concrete mixtures were prepared using Portland cements with alkali contents ranging from 0.45 % to 1.2 % Na2Oeq. Mineral aggregates consisted of blends of potentially reactive coarse granite and natural siliceous sand, characterized by varying degrees of reactivity. The development of concrete expansion over time and associated changes in its dynamic elastic modulus, as well as the characteristics of ASR products in concrete is reported. The chemical reactivity index was determined based on the concentrations of Si, Ca, and Al in test suspensions containing aggregate, CaO, and NaOH. At simulated pavement environmental conditions variations in temperature and relative humidity in concrete were monitored. The effects of exposure conditions on expansion behavior and the composition of ASR products are discussed. The alkali threshold levels derived for such different exposure conditions are compared and analyzed in relation to the varying potential reactivity of fine aggregates.

Keywords:
Alkali-silica reaction,Alkali supply,Concrete durability,Critical alkali content,NaCl deicer,Reactive aggregate,Simulated service exposure conditions

Pawłowski P., Stańczak M., Broniszewska-Wojdat P., Blanc L., Frąś T., Rusinek A., Energy-absorption capacity of additively manufactured AlSi10Mg cellular structures subjected to a blast-induced dynamic compression–experimental and numerical study, INTERNATIONAL JOURNAL OF IMPACT ENGINEERING, ISSN: 0734-743X, DOI: 10.1016/j.ijimpeng.2024.105216, Vol.198, No.10, pp.105216-1-105216-17, 2025

Abstract:
The study investigates the role of the topology of the additively manufactured AlSi10Mg cellular structures in the example of 3D and 2D designs: honeycomb, auxetic, lattice and foam. The samples were subjected to quasistatic and blast-induced dynamic compression. As a result, a relation between the structural geometry and the deformation mode of the compressed structures has been developed, demonstrating its influence on the energy absorption characteristics. The deformation and fracture mechanisms were examined in detail using the finite element simulations in the LS-DYNA code based on the material characterisation over a broad range of strain rates and temperatures. The outcomes show an agreement between the experimental data and the computations. The obtained results prove that by selecting the appropriate topological features, the deformation of compressed structures can be enhanced to improve their energy-absorption capacity.

Keywords:
Additive manufacturing,AlSi10Mg,Direct metal laser sintering (DMLS),Cellular structures,Dynamic compression,Blast-energy absorption,Explosively-driven shock tube

Mierzejewska I., Durejko T., Antolak-Dudka A., Zasada D., Kopeć M., Unravelling enhanced mechanical properties of LENS-manufactured Ti-5553 alloy through interlayer dwell control without post-processing heat treatment, JOURNAL OF ALLOYS AND COMPOUNDS, ISSN: 0925-8388, DOI: 10.1016/j.jallcom.2025.182893, No.182893, pp.1-18, 2025

Abstract:
Near-β titanium alloys such as Ti–5Al–5Mo–5V–3Cr (Ti-5553) are widely applied in aerospace and automotive industries due to their high strength and fracture toughness. While additive manufacturing (AM) via Laser Engineered Net Shaping (LENS) provides design flexibility for such alloys, their mechanical properties are directly dependent on extensive post-processing. This study demonstrates that the introduction of a 26-second interlayer dwell time during LENS fabrication enables in-situ microstructural tailoring, resulting in a distinctive α/β structure with Widmanstätten features and thus, eliminating the need for further heat treatment. The as-built Ti-5553 alloy achieved a superior combination of yield strength (1198 MPa) and ductility (16%), outperforming both heat-treated and conventionally processed counterparts. Comparative annealing at 300 °C, 700 °C, and 750 °C led to moderate changes in strength or ductility thus proving that the as-built condition is characterized by the most balanced performance. These findings highlights, that the proper interlayer dwell time selection enable achieving application-ready mechanical properties in β-Ti alloys directly from the AM process.

Keywords:
Ti-5553 titanium alloy,β-Ti alloys,Direct Energy Deposition (DED),Microstructure

Jóźwiak-Niedźwiedzka D., Rovnanik P., Dąbrowski M., Ośko J., Kuć M., Maciak M., Gamma radiation attenuation, mechanical properties and microstructure of barite-modified cement and geopolymer mortars, Nuclear Engineering and Technology, ISSN: 1738-5733, DOI: 10.1016/j.net.2024.10.057, Vol.57 (4), No.103295, pp.1-11, 2025

Abstract:
The present study contributes to the development of alternative materials for radiation shielding, focusing on environmental sustainability and material cost efficiency. The primary aim was to evaluate the compressive and flexural strength, mineral composition, microstructure, and gamma-ray attenuation properties of cement mortars and geopolymer mortars containing barite powder. Mortars based on ordinary Portland cement (OPC) and fly ash geopolymers with varying amounts of barite powder were assessed for their shielding properties at energy levels associated with the decay of 137Cs. From the results, key parameters such as the linear attenuation coefficient (μ), mass attenuation coefficient (μm), half-value layer (HVL), and tenth-value layer (TVL) were determined. The results showed that while cement-based composites exhibited superior gamma radiation attenuation compared to fly ash geopolymer mortars, the latter had higher mass attenuation efficiency, meaning less material density was required for the same level of shielding. Additionally, cement mortars had 23–25 % higher mechanical strength than geopolymer mortars. Importantly, the inclusion of barite powder improved the radiation shielding performance of both materials by 7–10 %, demonstrating its effectiveness in enhancing the protective properties of these mortars. This research highlights the potential of fly ash geopolymer mortars as viable, eco-friendly alternatives to traditional cement mortars in radiation shielding applications.

Keywords:
Cement mortar, Fly ash geopolymer mortar, Barite, Gamma ray attenuation, Microstructure

Kamiński J., Adamczyk-Cieślak B., Kopeć M., Kosiński A., Sitek R., Cover Picture: Materials and Corrosion. 3/2025: Effects of Reduction-Oxidation Cycles on the Structure, Heat and Corrosion Resistance of Haynes 282 Nickel Alloy Manufactured by using Powder Bed Fusion- Laser Beam Method, materials and corrosion, ISSN: 0947-5117, DOI: 10.1002/maco.202570031, pp.1-1, 2025

Keywords:
corrosion, DMLS, haynes 282, nickel superalloy, hydrogen , oxidation

Dziedzic K., Brachaczek A., Nowicki D., Glinicki M.A., Mitigation of Alkali–Silica Reactivity of Greywacke Aggregate in Concrete for Sustainable Pavements, Sustainability, ISSN: 2071-1050, DOI: 10.3390/su17156825, Vol.17, No.6825, pp.1-15, 2025

Abstract:
Quality requirements for mineral aggregate for concrete used to construct pavement for busy highways are high because of the fatigue traffic loads and environmental exposure. The use of local aggregate for infrastructure projects could result in important sustainability improvements, provided that the concrete’s durability is assured. The objective of this study was to identify the potential alkaline reactivity of local greywacke aggregate and select appropriate mitigation measures against the alkali–silica reaction. Experimental tests on concrete specimens were performed using the miniature concrete prism test at 60 °C. Mixtures of coarse greywacke aggregate up to 12.5 mm with natural fine aggregate of different potential reactivity were evaluated in respect to the expansion, compressive strength, and elastic modulus of the concrete. Two preventive measures were studied—the use of metakaolin and slag-blended cement. A moderate reactivity potential of the greywacke aggregate was found, and the influence of reactive quartz sand on the expansion and instability of the mechanical properties of concrete was evaluated. Both crystalline and amorphous alkali–silica reaction products were detected in the cracks of the greywacke aggregate. Efficient expansion mitigation was obtained for the replacement of 15% of Portland cement by metakaolin or the use of CEM III/A cement with the slag content of 52%, even if greywacke aggregate was blended with moderately reactive quartz sand. It resulted in a relative reduction in expansion by 85–96%. The elastic modulus deterioration was less than 10%, confirming an increased stability of the elastic properties of concrete.

Keywords:
alkali-silica reaction, aggregate, concreto, metakaolin, highway pavement

Nabavian Kalat M., Ziai Y., Dziedzic K., Gradys A. D., Urbański L., Zaszczyńska A., Andrés Díaz L., Kowalewski Z. L., Experimental evaluation of build orientation effects on the microstructure, thermal, mechanical, and shape memory properties of SLA 3D-printed epoxy resin, EUROPEAN POLYMER JOURNAL, ISSN: 0014-3057, DOI: 10.1016/j.eurpolymj.2025.113829, Vol.228, pp.113829-1-18, 2025

Abstract:
Additive manufacturing (AM) methods, popularly known as 3D printing technologies, particularly the pioneering laser stereolithography (SLA), have revolutionized the production of complex polymeric components. However, challenges such as anisotropy, resulting from the layer-by-layer construction method, can affect the thermomechanical properties and dimensional stability of 3D-printed objects. Although anisotropy in SLA 3D printing is often overlooked due to the high precision of this technique, its impact on the properties and structural performance of the 3D-printed prototype becomes more significant when printing small devices designed for precise micro-mechanisms. This experimental study investigates the impact of the chosen printing surface – a less explored factor – on the performance of SLA 4D-printed thermo-responsive shape memory epoxy (SMEp) specimens. Two identical dog-bone specimens were printed from two distinct surfaces: edge and flat surface, to examine how variations in surface area and quantity of layers influence the microstructure, thermal behavior, mechanical properties, and shape memory performance. The results of this experimental investigation reveal that specimens printed from the edge, with a higher number of layers and smaller surface area, exhibit superior interlayer bonding, tensile strength, dimensional stability, and shape recovery efficiency compared to those printed from the flat surface. Conversely, specimens with fewer, larger layers demonstrated greater elongation and thermal expansion but reduced structural integrity and shape recovery performance. These results highlight the importance of experimentally investigating how different build orientations affect the properties and performance of SLA 3D-printed materials, especially before designing and employing them in applications demanding high precision and reliability.

Keywords:
Additive manufacturing, Laser stereolithography, Shape memory polymers, Materials processing, Anisotropy, Printing orientation

Kopeć M., Gunputh U., Williams G., Wojcieck M., Kowalewski Z., Wood P., On the Cover: 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/s11340-025-01179-w, pp.1-1, 2025

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)

Sitek R., Bochenek K., Maj P., Marczak M., Żaba K., Kopeć M., Kaczmarczyk G., Kamiński J., Hot-Pressing of Ti-Al-N Multiphase Composite: Microstructure and Properties, Applied Sciences, ISSN: 2076-3417, DOI: 10.3390/app15031341, Vol.15, No.1341, pp.1-15, 2025

Abstract:
This study focuses on the development and characterization of a bulk Ti-Al-N
multiphase composite enriched with BN addition and sintered through hot pressing. The
research aimed to create a material with optimized mechanical and corrosion-resistant
properties suitable for demanding industrial applications. The composite was synthesized using a powder metallurgy approach with a mixture of AlN, TiN, and BN powders, processed under a high temperature and pressure. Comprehensive analyses, including microstructural evaluation, hardness testing, X-ray tomography, and electrochemical corrosion assessments, were conducted. The results confirmed the formation of a multiphase microstructure consisting of TiN, Ti₂AlN and Ti₃AlN phases. The microstructure was uniform with minimal porosity, achieving a hardness within the range of 500–540 HV2. Electrochemical tests revealed the formation of a passive oxide layer that provided moderate corrosion resistance in chloride-rich environment. However, localized pitting corrosion was observed under extreme conditions. The study highlights the potential of a BN admixture to enhance mechanical and corrosion-resistant properties and suggests directions for further optimization in sintering processes and material formulations.

Keywords:
AlN-TiN(BN) composite,hot-pressing,μCT,corrosion resistance

Tytko G., Adamczyk-Habrajska M., Linke Y., Pengpeng S., Kopeć M., Eddy Current Method in Non-Magnetic Aluminide Coating Thickness Assessment, JOURNAL OF NONDESTRUCTIVE EVALUATION, ISSN: 0195-9298, DOI: 10.1007/s10921-025-01211-y, Vol.44, No.65, pp.1-11, 2025

Abstract:
This study investigates the use of eddy current testing (ECT) as a non-destructive technique to evaluate the thickness and structural variations of non-magnetic aluminide coatings on MAR-M247 nickel-based superalloy. Coatings with thicknesses of 20 μm and 40 μm were applied to substrates exhibiting fine, coarse, and columnar grain structures. Using sensors of different geometries, impedance measurements were performed within a frequency range of 11.5 MHz to 12.5 MHz. Results demonstrated the designed sensor’s superior sensitivity, with the highest values of absolute resistance difference significantly exceeding the threshold for reliable distinction due to coating thicknesses or grain structures. The study highlights the impact of eddy current penetration depth and edge effects on the measurement accuracy, emphasizing the need for optimized sensor design and frequency selection. Findings confirm the efficacy of ECT in differentiating coatings of varying thicknesses and substrate structures, offering a reliable tool for quality control in high-temperature applications.

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

Szczęsny G., Kopeć M., Kowalewski Z. L., Toxicity, Irritation, and Allergy of Metal Implants: Historical Perspective and Modern Solutions, Coatings, ISSN: 2079-6412, DOI: 10.3390/coatings15030361, Vol.15, No.361, pp.1-32, 2025

Abstract:
The widespread adoption of metal implants in orthopaedics and dentistry has revolutionized medical treatments, but concerns remain regarding their biocompatibility, toxicity, and immunogenicity. This study conducts a comprehensive literature review of traditional biomaterials used in orthopaedic surgery and traumatology, with a particular focus on their historical development and biological interactions. Research articles were gathered from PubMed andWeb of Science databases using keyword combinations such as “toxicity, irritation, allergy, biomaterials, corrosion, implants, orthopaedic surgery, biocompatible materials, steel, alloys, material properties, applications, implantology, and surface modification”. An initial pool of 400 articles was screened by independent reviewers based on predefined inclusion and exclusion criteria, resulting in 160 relevant articles covering research from 1950 to 2025. This paper explores the electrochemical processes of metals like iron, titanium, aluminium, cobalt, molybdenum, nickel, and chromium post-implantation, which cause ion release and wear debris formation. These metal ions interact with biological molecules, triggering localized irritation, inflammatory responses, and immune-mediated hypersensitivity. Unlike existing reviews, this paper highlights how metal–protein interactions can form antigenic complexes, contributing to delayed hypersensitivity and complications such as peri-implant osteolysis and implant failure. While titanium is traditionally considered bioinert, emerging evidence suggests that under certain conditions, even inert metals can induce adverse biological effects. Furthermore, this review emphasizes the role of oxidative stress, illustrating how metal ion release and systemic toxicity contribute to long-term health risks. It also uncovers the underappreciated genotoxic and cytotoxic effects of metal ions on cellular metabolism, shedding light on potential long-term repercussions. By integrating a rigorous methodological approach with an in-depth exploration of metal-induced biological responses, this paper offers a more nuanced perspective on the complex interplay between metal implants and human biology, advancing the discourse on implant safety and material innovation.

Keywords:
orthopaedic implants, toxicity, metals, biomaterials

Haponova O., Tarelnyk V., Mościcki T., Tarelnyk N., Hybrid Surface Treatment Technologies Based on the Electrospark Alloying Method: A Review, Coatings, ISSN: 2079-6412, Vol.15, No.6, pp.1-26, 2025

Abstract:
Technologies for functional coatings are evolving rapidly, with electrospark alloying (ESA) emerging as a promising method for surface modification due to its efficiency and localized impact. This review analyzes the fundamental principles of ESA and the effects of process parameters on coating characteristics and highlights its advantages and limitations. Particular attention is given to hybrid ESA-based technologies, including combinations with laser treatment, plastic deformation, vapor deposition, and polymer-metal overlays. These hybrid methods significantly improve coating quality by enhancing hardness, adhesion, and structural integrity and reducing roughness and defects. However, the multi-parameter nature of these processes presents optimization challenges. This review identifies knowledge gaps related to process reproducibility, control of microstructure formation, and long-term performance under service conditions. Recent breakthroughs in combining ESA with high-energy surface treatments are discussed. Future research should focus on systematic parameter optimization, in situ diagnostics, and predictive modeling to enable the design of application-specific hybrid coatings.

Keywords:
electrospark alloying, hybrid technologies, surface plastic deformation, laser treatment, vapor phase deposition, metal–polymer material, coating, structure, properties, roughness, coating quality, sustainable development goals

Rzempołuch J., Stasiak T., Maździarz M., Jasiński J., Woy U., Psiuk R., Kowal M., Kosińska A., Wilczopolska M., Mulewska K., Barlak M., Ciporska K., Kurpaska Ł., Jagielski J., Mościcki T., Characterization of He+ implanted W-Zr-B thin films deposited by HiPIMS on additively manufactured Inconel 617 as a candidate system for nuclear components, Journal of Nuclear Materials, ISSN: 0022-3115, DOI: 10.1016/j.jnucmat.2025.156091, Vol.616, No.156091, pp.1-12, 2025

Abstract:
Tungsten boride alloyed with zirconium is considered a very promising material in the nuclear industry due to its shielding properties. In this paper, the resistance to helium irradiation of W-Zr-B thin films deposited on additively manufactured Inconel 617 is investigated. Two laser Directed Energy Deposition methods, a laser powder (DED-LP) and laser wire (DED-LW) were utilized for Inconel 617 substrate preparation. Preliminary studies with density functional theory (DFT) calculations were performed to determine the stability and theoretical values of structural and mechanical properties of fabricated coatings. Additionally to structural and mechanical properties, an irradiation effects after ion implantation of the layers at room temperature and 400 °C with He+ ion dose of 5 × 10¹⁷ ions/cm² and energy of 60 keV were also studied. The results show that HiPIMS is a reliable process that allows depositing dense and uniform coatings with excellent mechanical properties, comparable with DFT calculations. Scratch test results confirmed good adhesion to the surface regardless of the substrate despite low critical forces values (5.4 N and 6.6 N Lc3 values). The thickness of the deposited coatings varied from 2.40 to 2.50 µm. Nevertheless, after helium ion implantation, TEM observation shows helium voids and bubbles form at the near-surface area of the coatings. A significant decrease in hardness from initial 21.12 GPa to 6.51 GPa (LW), 7.83 GPa (LP) after room temperature and 9.40 GPa (LW), 9.71 GPa (LP) after 400 °C ion implantation, respectively is observed. The mechanism underlying this effect is also discussed in the article.

Keywords:
Tungsten borides, Hard thin films, High-power impulse magnetron sputtering, He+ ion implantation, Nanoindentation

Kondej A., Kukla D., Wachulak P., Zagórski A., Non-destructive method of characterizing nitrided layers in the 42CrMo4 steel using the amplitude-frequency technique of eddy currents, Open Engineering , ISSN: 2391-5439, DOI: 10.1515/eng-2025-0106, Vol.15, No.1, pp.1-11, 2025

Abstract:
The aim of this work was to investigate the possibility of using the eddy current method, a technique for measuring voltage amplitude and resonant frequency, for non-destructive assessment of the thickness of the near-surface layer of iron nitrides in 42CrMo4 steel after gas nitriding. The scope of the work included preparation of test samples, chemical composition tests, surface roughness measurements, hardness distribution using the Vicker’s method and measurements of the thickness of nitrided layer on cross-sections, X-ray phase composition analysis, testing of nitrided layer using the eddy current method, analysis of the correlation of the results of destructive and non-destructive tests. The main research apparatus was the Wirotest M2 with the 25 kHz measuring head. Differences in electromagnetic parameters between the white layer and the rest of the nitrided material, as well as changes in the surface roughness of the layer, are factors influencing the eddy current signal, which allows indirect measurement of its thickness. The analysis of the voltage amplitude is more accurate, than the resonant frequency, in assessing the thickness of nitrides layer. With the increase in thickness of the nitrides layer, the voltage value of the signal of eddy currents increases. The research results also indicate the possibility of using the same measuring head to assess the roughness parameter Ra of the nitrided layer. The Wirotest M2 can be used in quality control of steel parts after nitriding.

Keywords:
non-destructive testing, eddy currents, gas nitriding, nitrides zone, thickness measurement, voltage amplitude

Kukla D., Kondej A., Jończyk S., Lasota P., Tabin J., Schob D., Roszak R., Kawałko J., Zagórski A., Kopeć M., Eddy current methodology in the non-direct measurement of martensite during plastic deformation of SS316L, Open Engineering , ISSN: 2391-5439, Vol.15(1), No.20250118, pp.1-9, 2025

Abstract:
This study examines the use of various eddy current induction techniques to evaluate the stability of austenite in SS316L steel subjected to plastic deformation. This deformation, which occurs locally in austenitic steel structures under operational loads, leads to a martensitic transformation. This transformation affects both the mechanical and magnetic properties of the steel. The martensitic phase content, being ferromagnetic, can be quantitatively assessed using a ferritoscope and other magnetic induction methods. The research explores techniques based on the analysis of impedance signal changes obtained using the NORTEC defetoscope and the WIROTEST device developed by the author’s team. By examining the phase angle, ET signal amplitude, and resonance frequency changes in the eddy current excitation system, the study aims to quantitatively assess the martensitic phase content in samples subjected to plastic deformation. These results were verified through comparison with data from a ferritoscope and X-ray diffraction analysis. Additionally, the eddy current technique facilitates surface screening of the specimen, making it possible to identify cracks and locate the martensitic transformation front in areas of stress concentration.

Keywords:
eddy current, martensitic transformation, additive manufacturing, stainless steel, non-destructive testing, WIROTEST device

Tarelnyk V., Haponova O., Tarelnyk N., Konoplianchenko Y., Sulphurizing of Metal Surfaces by Electrospark-Discharge Alloying. Pt. 1: Structural–Phase State of Sulphur-Containing Coatings on Constructional Steels, Uspekhi Fiziki Metallov, ISSN: 1608-1021, Vol.26, No.1, pp.146-200, 2025

Abstract:
The methods of surface sulphur saturation of metal surfaces to provide them with special tribotechnical properties are reviewed and analysed. The main attention is focused on technologies based on the method of electrospark alloying (ESA). As shown, the process of sulphur saturation can be realised by using a special sulphur-containing saturating technical substance (STS). The methods of forming sulphided, sulphocarburized, sulphoaluminized, Al–C–S, and sulphomolybdenum coatings on steels using STS by ESA are considered. The results of sulphur distribution in the surface layer during ESA sulphurizing with a metal electrode using STS are presented. As shown, the sulphur concentration on the surface is of about 0.53–0.60% that gradually decreases deeper into the substrate. The topography of the treated surface and its structure after sulphocarburized of steel surfaces with a graphite electrode using STS containing sulphur are investigated. As found, the coating consists of several layers: a ‘soft’ layer saturated with sulphur, a hardened layer saturated with carbon, and the substrate metal. The thickness, microhardness, and continuity of the coating increase with the discharge energy. The qualitative parameters of sulphoaluminized coatings obtained by the ESA method with an aluminium electrode using STS are analysed. The microstructures reveal three zones: a near-surface, non-continuous loose layer with sulphur enrichment, 10–100-µm thick, and microhardness of 1368–2073 MPa; a ‘white’ hardened layer containing aluminium, 20–40 µm-thick, and microhardness of 4094–5157 MPa; a diffusion zone; and a substrate material. The sulphoaluminized-coatings’ phase composition depends on the ESA energy parameters. Intermetallics FeAl and FeAl2 are formed in the surface layer. The structural–phase state and properties of sulphomolybdenum coatings obtained by the ESA method with a molybdenum electrode using STS are discussed. The near-surface loose layer saturated with sulphur contains up to 8% of molybdenum disulphide formed due to ESA. Beneath this layer is a hardened layer saturated with molybdenum and having a microhardness of 10596–10731 MPa. It is proposed to use sulphurizing methods based on ESA using STS as cheap and effective methods of surface modification of friction surfaces to reduce seizure and friction coefficient.

Keywords:
sulphurizing, electrospark alloying, coating, microstructure, tribotechnical properties

Tarelnyk V., Haponova O., Tarelnyk N., Konoplianchenko Y., Sulphurizing of Metal Surfaces by Electrospark-Discharge Alloying. Pt. 2: Tribological Properties of Electrospark Depositing Sulphur-Containing Coating, Uspekhi Fiziki Metallov, ISSN: 1608-1021, Vol.26, No.2, pp.111-222, 2025

Abstract:
The essence and technological characteristics of the electrospark alloying (ESA) process, its advantages and disadvantages have been considered in order to use it to improve the tribological properties of bronze and steel parts. A generalization of the available data and results in the literature concerned with the ESA process has been made. Based on the published data, a comparative analysis of various methods for forming combined electrospark coatings (CESC) on bronzes, which include sulphur, the influence of the mode parameters and the compositions of the CESC on the microstructure, mechanical and tribological properties are represented. The methods for practical application in production have been proposed. The methods for forming the self-lubricating electrospark coatings containing molybdenum disulphide on steel substrates have been investigated. There have been represented physical and mechanical characteristics of the coatings, which had been obtained using different strategies, as well as there has been disclosed the nature of their changes depending on the technological parameters of the ESA modes and the types of the starting materials for the anode and cathode, and on the compositions of the environment wherein the ESA process takes place. There have been given the summarized data on the tribological properties of the coatings, which had been obtained on some steel grades using different electrode materials and modes of operation. As demonstrated, the ESA method can be successfully used to reduce the coefficient of friction and to increase the wear resistance of bronze and steel surfaces. There have been specified the proposed electrode materials and ESA process parameters for modifying the surfaces made of some bronzes and steels.

Keywords:
technology, electrospark alloying, coating, microstructure, tribotechnical properties

Kopeć M., Kukla D., Kowalewski Z., Assessment of aluminide coating integrity by using acoustic emission, JOURNAL OF THEORETICAL AND APPLIED MECHANICS, ISSN: 1429-2955, DOI: 10.15632/jtam-pl/203353 , pp.1-6, 2025

Abstract:
Coatings are essential for protecting high-temperature components in aerospace and power generation industries. This study evaluates the integrity of aluminide coatings on MAR-M247, a nickelbased superalloy, under uniaxial tensile loading using acoustic emission (AE). Aluminide coatings, deposited via chemical vapor deposition (CVD), provide oxidation and corrosion resistance but are prone to damage under operational stresses. AE monitoring, a nondestructive evaluation method, detects transient elastic waves associated with damage events such as crack initiation and delamination. By analyzing AE signal characteristics like amplitude and energy, this research identifies acoustic signatures indicative of coating degradation. The findings highlight AE’s potential for real-time damage assessment, enabling early detection and predictive maintenance strategies in high-temperature applications.

Keywords:
coatings,acoustic emission,nickel alloys,non destructive testing

Kopeć M., Digital image correlation in monitoring of fatigue damage development of MAR-M247 with aluminide coating, JOURNAL OF THEORETICAL AND APPLIED MECHANICS, ISSN: 1429-2955, pp.1-6, 2025

Abstract:
This study investigates the fatigue damage development in MAR-M247, a nickel-based superalloy with aluminide coating, using the digital image correlation (DIC) technique. The alloy’s microstructures, including fine, coarse, and columnar grains, were analyzed to understand their influence on fatigue crack initiation and propagation. Fatigue tests were conducted at room temperature under controlled force, with strain evolution monitored through non-contact full-field DIC measurements. Results revealed that fine-grained MAR-M247 exhibited superior fatigue resistance due to uniform strain distribution, while coarse-grained and columnar structures showed pronounced strain localization and earlier crack initiation. The application of aluminide coatings did not significantly affect strain distribution across the different microstructures but highlighted complex interactions between coating and grain structure under cyclic loading. These findings provide critical insights into optimizing the performance of MAR-M247 for high-stress applications

Keywords:
fatigue, coatings, nickel alloys, digital image correlation

Dubey V.P., Kopeć M., Kowalewski Z., Experimental identification of CP-Cu yield surface and its evolution due to complex loading pre-deformation, JOURNAL OF THEORETICAL AND APPLIED MECHANICS, ISSN: 1429-2955, pp.1-14, 2025

Abstract:
This study examines the yield surface evolution of technical copper (CP-Cu) under complex loading, focusing on monotonic tension and combined tension with cyclic torsion. Using biaxial testing, initial and pre-deformed yield surfaces were analysed. Results indicate kinematic hardening with tensile pre-strain, while cyclic torsion induces anisotropic hardening at lower amplitudes (±0.1 %) and softening at higher amplitudes (±0.2 %). Strain amplitude significantly impacts material response, while frequency has a minor effect

Keywords:
copper,pre-deformation,yield Surface,biaxial

Kukla D., Kowalewski Z., Kopeć M., Assessment of microstructural changes in S235 steel after cold rolling using eddy current testing, JOURNAL OF THEORETICAL AND APPLIED MECHANICS, ISSN: 1429-2955, pp.1-6, 2025

Abstract:
This study investigates the eddy current testing (ECT) technique to assess microstructural changes in S235 low carbon steel after cold rolling. Specimens of varying thicknesses (12 mm, 8 mm, and 6mm) were analyzed to evaluate the impact of deformation on such properties as dislocation density, grain texture, and hardness. Metallographic studies using light microscopy were performed, supplemented by dislocation density measurements via transmission electron microscopy (TEM). The ECT results demonstrated that microstructural changes, particularly cold-work hardening and grain elongation, significantly influenced the phase angle of impedance. Lower penetration depths were more sensitive to surface changes, highlighting the capacity of ECT for detecting nearsurface deformation. This work establishes a robust, non-destructive methodology for characterizing manufacturing-induced microstructural changes in heat-resistant steels, with applications in quality control and material performance evaluation

Keywords:
cold rolling, eddy current, microstructure

Szymczak T., Kowalewski Z., Brodecki A., Durability tests for the automotive industry, JOURNAL OF THEORETICAL AND APPLIED MECHANICS, ISSN: 1429-2955, DOI: 10.15632/jtam-pl/200388, Vol.63, No.3, pp.461-469, 2025

Abstract:
This study focuses on component durability testing methods and their application in the automotive industry. These types of tests can be used to assess various objects with simple and complex geometries and a range of dimensions, manufactured using certain structural materials, including 6005 T6 aluminium alloy and S700MC high-strength steel. The test results characterise the component response at 2×106 loading cycles, and the crack trajectories are analysed after a high number of cycles. The influence of the welding process on the tensile mechanical parameters of the aluminium alloy and steel is also discussed, and fatigue behaviour of S700MC and its weld are illustrated

Keywords:
durability test, fatigue, cracks, fracture, coupling, vehicles

Makowska K., Szymczak T., Kowalewski Z.L., Exploitation parameters of deformed high-strength steel assessed by the Barkhausen noise method, JOURNAL OF THEORETICAL AND APPLIED MECHANICS, ISSN: 1429-2955, Vol.63, No.3, pp.657-672, 2025

Abstract:
The elastic limit, yield point, strain hardening component, and strength coefficient of martensitic steel were determined after monotonic tensile loading. The monotonic tension test of 41Cr4 steel was conducted for selected values of deformation. The specimen was unloaded after each pre-strain. The parameters from destructive tests were compared with those from the Barkhausen noise (BN) method obtained. It turned out that the magnetic Barkhausen effect can be helpful in the diagnostics of structural steel components and devices. Linear relationships between the elastic limit/yield point and parameters coming from the rms voltage of Barkhausen noise envelope were found

Keywords:
yield point, elastic limit, strain hardening component, strength coefficient, magnetic Barkhausen noise

Tarelnyk V., Haponova O., Tarelnyk N., Rogovskii I., IMPROVEMENT OF SURFACE LAYER QUALITY PARAMETERS OF STEEL PARTS AFTER NITROСARBURUZING BY ELECTROSPARK ALLOYING METHOD Part 1 FEATURES OF THE STRUCTURAL STATE AND TOPOGRAPHY OF STEEL SURFACES AFTER NITROCARBURIZING, Problems of Atomic Science and Technology, ISSN: 1562-6016, Vol.156, No.2, pp.131-137, 2025

Abstract:
The paper analyses modern methods for improving the surface quality of steel parts of nuclear power plant pumps. The aim of the work was to improve the technology of nitrocarburisation by the method of electrospark alloying (ESA) by studying the effect of the ESA process performance on the quality parameters of the formed surfaces. As a result of the studies, the dependence of the quality parameters of the surfaces of steel parts during nitrocarburizing by the ESA method on the energy parameters of the equipment (discharge energy Wp) and the technological parameters of the process (productivity Q) was established. Experimental studies have shown that as Wp increases, the thickness of the hardened layer, its microhardness and continuity, and surface roughness grow. As Q decreases, the thickness, microhardness and continuity of the hardened layer rise, while the roughness remains practically unchanged. The proposed technology can be recommended for implementation in manufacturing