Pub Date : 2025-12-24DOI: 10.1016/j.mtla.2025.102648
R. Fréville , P.A. Gruber , S. Lee , J.S. Micha , O. Robach , O. Ulrich , C. Kirchlechner
Femtosecond laser (fs-laser) milling has emerged as a promising technique for high-precision material processing, offering significantly faster ablation rates compared to Ga+ Focused Ion Beam (FIB) milling. While fs-laser ablation is often considered to be athermal, its impact on surface features, such as redeposited material, raises concerns about its influence on microstructure and residual stress fields. This study explores the mechanical effects of fs-laser and FIB milling on a germanium single crystal, using synchrotron-based Laue microdiffraction coupled with Digital Image Correlation to characterize induced residual stresses and their spatial distribution. The further development of this technique allows to push the strain resolution to 10⁻⁵, which enabled a clear identification of the influence of the redeposition structure.
{"title":"Residual stress in Germanium single crystals caused by femtosecond laser micromachining","authors":"R. Fréville , P.A. Gruber , S. Lee , J.S. Micha , O. Robach , O. Ulrich , C. Kirchlechner","doi":"10.1016/j.mtla.2025.102648","DOIUrl":"10.1016/j.mtla.2025.102648","url":null,"abstract":"<div><div>Femtosecond laser (fs-laser) milling has emerged as a promising technique for high-precision material processing, offering significantly faster ablation rates compared to Ga<sup>+</sup> Focused Ion Beam (FIB) milling. While fs-laser ablation is often considered to be athermal, its impact on surface features, such as redeposited material, raises concerns about its influence on microstructure and residual stress fields. This study explores the mechanical effects of fs-laser and FIB milling on a germanium single crystal, using synchrotron-based Laue microdiffraction coupled with Digital Image Correlation to characterize induced residual stresses and their spatial distribution. The further development of this technique allows to push the strain resolution to 10⁻⁵, which enabled a clear identification of the influence of the redeposition structure.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"45 ","pages":"Article 102648"},"PeriodicalIF":2.9,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-24DOI: 10.1016/j.mtla.2025.102647
Archana R. Kanwade , Minaj M. Faras , Jena Akash Kumar Satrughna , Shraddha M. Rajore , Sawanta S. Mali , Jyoti V. Patil , Chang Kook Hong , Parasharam M. Shirage
Sodium-ion batteries (SIBs) have emerged as a promising alternative to lithium-ion systems due to the abundance and cost-effectiveness of sodium resources; however, their development is hindered by the lack of high-performance anode materials. Spinel ZnCo2O4 (ZCO) is considered a favorable candidate owing to its high theoretical capacity, multiple redox-active sites, and tunable morphology. Herein, ZCO is directly grown on nickel foam (NF) via a hydrothermal reaction, developing a binder-free ZCO/NF electrode. Urea is employed as a structure-directing agent, resulting in a unique neem leaf-like morphology of the ZCO/NF. Further, the ZCO/NF was structurally and morphologically characterized by physicochemical techniques. When evaluated as an anode material for SIBs, it demonstrated outstanding electrochemical performance. The ZCO/NF exhibited an irreversible discharge capacity of 1893.73 mAh/g and a reversible capacity of 863.79 mAh/g at a current density of 10 mA/g, along with excellent rate capability. At a current density of 50 mA/g, it retains 42.12% of its capacity after 300 cycles. This electrochemical performance of ZCO/NF is attributed to multiple sodium storage mechanisms, including conversion reactions, limited intercalation, and pseudocapacitive surface redox processes. This study highlights the potential of ZCO/NF as a high-performance, binder-free anode material for next-generation rechargeable energy storage systems.
{"title":"Intercalation-conversion and pseudocapacitive coupled sodium storage in binder-free ZnCo2O4 anode","authors":"Archana R. Kanwade , Minaj M. Faras , Jena Akash Kumar Satrughna , Shraddha M. Rajore , Sawanta S. Mali , Jyoti V. Patil , Chang Kook Hong , Parasharam M. Shirage","doi":"10.1016/j.mtla.2025.102647","DOIUrl":"10.1016/j.mtla.2025.102647","url":null,"abstract":"<div><div>Sodium-ion batteries (SIBs) have emerged as a promising alternative to lithium-ion systems due to the abundance and cost-effectiveness of sodium resources; however, their development is hindered by the lack of high-performance anode materials. Spinel ZnCo<sub>2</sub>O<sub>4</sub> (ZCO) is considered a favorable candidate owing to its high theoretical capacity, multiple redox-active sites, and tunable morphology. Herein, ZCO is directly grown on nickel foam (NF) via a hydrothermal reaction, developing a binder-free ZCO/NF electrode. Urea is employed as a structure-directing agent, resulting in a unique neem leaf-like morphology of the ZCO/NF. Further, the ZCO/NF was structurally and morphologically characterized by physicochemical techniques. When evaluated as an anode material for SIBs, it demonstrated outstanding electrochemical performance. The ZCO/NF exhibited an irreversible discharge capacity of 1893.73 mAh/g and a reversible capacity of 863.79 mAh/g at a current density of 10 mA/g, along with excellent rate capability. At a current density of 50 mA/g, it retains 42.12% of its capacity after 300 cycles. This electrochemical performance of ZCO/NF is attributed to multiple sodium storage mechanisms, including conversion reactions, limited intercalation, and pseudocapacitive surface redox processes. This study highlights the potential of ZCO/NF as a high-performance, binder-free anode material for next-generation rechargeable energy storage systems.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"45 ","pages":"Article 102647"},"PeriodicalIF":2.9,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-23DOI: 10.1016/j.mtla.2025.102637
Bernhard Bloder , Bernd Schuscha , Dominik Brandl , Thomas Antretter , Peter Raninger
In this work we develop a bainite model which can describe bainite formation for arbitrary cooling conditions. To investigate the influence of carbon on bainite formation, the model is applied to a set of steels with different carbon concentrations and heat treatments. For the investigated steels the temperature and the prior austenite grain size are measured and used in the calculation. The redistribution of carbon is considered and the respective parameters are given a carbon dependency. The efforts to get a consistent set of parameters are laid out. The calculations for isothermal bainite formation and bainite formation upon continuous cooling are compared to data from dilatometer and XRD measurements.
{"title":"Modeling the bainite transformation kinetics during isothermal holding and continuous cooling for different carbon concentrations","authors":"Bernhard Bloder , Bernd Schuscha , Dominik Brandl , Thomas Antretter , Peter Raninger","doi":"10.1016/j.mtla.2025.102637","DOIUrl":"10.1016/j.mtla.2025.102637","url":null,"abstract":"<div><div>In this work we develop a bainite model which can describe bainite formation for arbitrary cooling conditions. To investigate the influence of carbon on bainite formation, the model is applied to a set of steels with different carbon concentrations and heat treatments. For the investigated steels the <span><math><msubsup><mrow><mi>T</mi></mrow><mrow><mn>0</mn></mrow><mrow><msup><mrow></mrow><mrow><mo>′</mo></mrow></msup></mrow></msubsup></math></span> temperature and the prior austenite grain size are measured and used in the calculation. The redistribution of carbon is considered and the respective parameters are given a carbon dependency. The efforts to get a consistent set of parameters are laid out. The calculations for isothermal bainite formation and bainite formation upon continuous cooling are compared to data from dilatometer and XRD measurements.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"45 ","pages":"Article 102637"},"PeriodicalIF":2.9,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145885049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-23DOI: 10.1016/j.mtla.2025.102646
Qiqi Li , Fanjiao He , Congrui Xie , Kai Liu , Hui Gao , Ping Zou , Lin Hu
In this study, inspired by the design of a step-folding cup, a similar structure, the novel folded cup energy absorption structure (FES), was proposed. This structure is fabricated using selective laser sintering (SLS) technology with nylon 11. Through rigorous simulation analysis, the energy absorption characteristics of the FES have been systematically elucidated. Subsequently, the deformation behavior and mechanical properties under axial compression were investigated using finite element analysis (FEA) and practical experimentation. FES achieves unique mechanical characteristics, including negative stiffness and a novel deformation mode. To validate the effectiveness of the proposed structure, a comparative analysis was conducted between experimental and simulation results. This paper analyzes the compressive mechanical properties of the FES from four perspectives: the diameter of each layer, the thickness of the inclined buffer layer, the number of layers, and the proportion of the inclined buffer layer at the end. The findings demonstrate that a decrease in diameter deviation, in essence, is positively correlated with both the dimensional ratio and the thickness of the inclined buffer layer, leading to significantly improved energy absorption capabilities in the FES model. Compared to the experimental benchmark model, the parametric model demonstrates up to 112.58% enhancement in specific energy absorption.
{"title":"A novel folded cup energy absorption structure: Design and validation","authors":"Qiqi Li , Fanjiao He , Congrui Xie , Kai Liu , Hui Gao , Ping Zou , Lin Hu","doi":"10.1016/j.mtla.2025.102646","DOIUrl":"10.1016/j.mtla.2025.102646","url":null,"abstract":"<div><div>In this study, inspired by the design of a step-folding cup, a similar structure, the novel folded cup energy absorption structure (FES), was proposed. This structure is fabricated using selective laser sintering (SLS) technology with nylon 11. Through rigorous simulation analysis, the energy absorption characteristics of the FES have been systematically elucidated. Subsequently, the deformation behavior and mechanical properties under axial compression were investigated using finite element analysis (FEA) and practical experimentation. FES achieves unique mechanical characteristics, including negative stiffness and a novel deformation mode. To validate the effectiveness of the proposed structure, a comparative analysis was conducted between experimental and simulation results. This paper analyzes the compressive mechanical properties of the FES from four perspectives: the diameter of each layer, the thickness of the inclined buffer layer, the number of layers, and the proportion of the inclined buffer layer at the end. The findings demonstrate that a decrease in diameter deviation, in essence, is positively correlated with both the dimensional ratio and the thickness of the inclined buffer layer, leading to significantly improved energy absorption capabilities in the FES model. Compared to the experimental benchmark model, the parametric model demonstrates up to 112.58% enhancement in specific energy absorption.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"45 ","pages":"Article 102646"},"PeriodicalIF":2.9,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-18DOI: 10.1016/j.mtla.2025.102645
Galina G. Maier, Elena G. Astafurova
We study phase transformations and recrystallization during the high-temperature annealing (500 °C – 800 °C) of three nanostructured austenitic TWIP steels with a high fraction of twinning boundaries. Before annealing, model twin-assisted microstructures were created in the single-crystalline Fe-13Mn-1.3C (Hadfield steel), Fe-13Mn-2.7Al-1.3C, Fe-28Mn-2.7Al-1.3C steels by high-pressure torsion. The highest density of twin boundaries and scalar dislocation density was generated in Fe-13Mn-1.3C (ρtw = 25 × 1013 m-2) and the lowest one in Fe-28Mn-2.7Al-1.3C steel (ρtw = 8 × 1013 m-2). HPT-induced high defect density promotes primary recrystallization in the steels, starting at 500 °C in specimens of Hadfield steel, while twin-assisted nanostructures remain unaffected in two other steels with lower densities of twin boundaries and dislocations. Deformation defects act as primary sites for austenite decomposition γC→α(α′)+M3C or γC→γ+α(α′)+M3C during post-deformation annealing, providing formation of a nanocrystalline heterophase structure (γ+α(α′)+M3C). A direct comparison of two Al-alloyed steels with similar twinning and dislocation densities reveals that the decomposition of austenite in the HPT-deformed microstructure depends on steel composition rather than twin boundaries: it starts at lower annealing temperatures and is more complete in Fe-13Mn-2.7Al-1.3C steel compared to Fe-28Mn-2.7Al-1.3C one. No special role of deformation twins in the migration of grain boundaries or interphase boundaries during annealing at temperatures above 500 °C has been revealed.
{"title":"High-temperature recrystallization behavior and phase transformations in austenitic Fe-Mn-(Al)-C TWIP steels pre-deformed by high-pressure torsion","authors":"Galina G. Maier, Elena G. Astafurova","doi":"10.1016/j.mtla.2025.102645","DOIUrl":"10.1016/j.mtla.2025.102645","url":null,"abstract":"<div><div>We study phase transformations and recrystallization during the high-temperature annealing (500 °C – 800 °C) of three nanostructured austenitic TWIP steels with a high fraction of twinning boundaries. Before annealing, model twin-assisted microstructures were created in the single-crystalline Fe-13Mn-1.3C (Hadfield steel), Fe-13Mn-2.7Al-1.3C, Fe-28Mn-2.7Al-1.3C steels by high-pressure torsion. The highest density of twin boundaries and scalar dislocation density was generated in Fe-13Mn-1.3C (<em>ρ<sub>tw</sub></em> = 25 × 10<sup>13</sup> m<sup>-2</sup>) and the lowest one in Fe-28Mn-2.7Al-1.3C steel (<em>ρ<sub>tw</sub></em> = 8 × 10<sup>13</sup> m<sup>-2</sup>). HPT-induced high defect density promotes primary recrystallization in the steels, starting at 500 °C in specimens of Hadfield steel, while twin-assisted nanostructures remain unaffected in two other steels with lower densities of twin boundaries and dislocations. Deformation defects act as primary sites for austenite decomposition γ<sub>C</sub>→α(α′)+M<sub>3</sub>C or γ<sub>C</sub>→γ+α(α′)+M<sub>3</sub>C during post-deformation annealing, providing formation of a nanocrystalline heterophase structure (γ+α(α′)+M<sub>3</sub>C). A direct comparison of two Al-alloyed steels with similar twinning and dislocation densities reveals that the decomposition of austenite in the HPT-deformed microstructure depends on steel composition rather than twin boundaries: it starts at lower annealing temperatures and is more complete in Fe-13Mn-2.7Al-1.3C steel compared to Fe-28Mn-2.7Al-1.3C one. No special role of deformation twins in the migration of grain boundaries or interphase boundaries during annealing at temperatures above 500 °C has been revealed.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"45 ","pages":"Article 102645"},"PeriodicalIF":2.9,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The origin of the selection of slip systems in the transformation-induced dislocations after the B2–B19′ forward and reverse transformations in Ti–Ni shape memory alloys was investigated. To this end, habit plane of a finely twinned martensite plate was modeled in a zig-zag shape, and a geometrical measure was introduced to quantify the incompatibility of the transition layer. This measure was defined based on a simplified displacement field that was geometrically constructed to ensure compatibility between the transition layer and its surroundings. Using this measure, the effectiveness of each slip system in accommodating the incompatibility was evaluated, and the slip system most effective in accommodating the local incompatibility was identified. As a result, it was found that the slip system that can accommodate the incompatibility most effectively is the slip system whose slip plane is nearly parallel to the twin boundaries of lattice invariant deformation for each habit plane variant. These slip systems correspond to the experimentally identified slip systems in the many previous studies. Based on this result, the selection of the slip system of the transformation-induced dislocations can be explained geometrically and thermodynamically as a tendency to minimize the strain energy of the system by accommodating the incompatibility in the transition layer.
{"title":"Geometric accommodation of local incompatibility of parent/martensite interface by transformation-induced dislocations in Ti–Ni","authors":"Gen Hikosaka , Yuri Shinohara , Ryutaro Matsumura , Minoru Nishida , Tomonari Inamura","doi":"10.1016/j.mtla.2025.102624","DOIUrl":"10.1016/j.mtla.2025.102624","url":null,"abstract":"<div><div>The origin of the selection of slip systems in the transformation-induced dislocations after the B2–B19′ forward and reverse transformations in Ti–Ni shape memory alloys was investigated. To this end, habit plane of a finely twinned martensite plate was modeled in a zig-zag shape, and a geometrical measure was introduced to quantify the incompatibility of the transition layer. This measure was defined based on a simplified displacement field that was geometrically constructed to ensure compatibility between the transition layer and its surroundings. Using this measure, the effectiveness of each slip system in accommodating the incompatibility was evaluated, and the slip system most effective in accommodating the local incompatibility was identified. As a result, it was found that the slip system that can accommodate the incompatibility most effectively is the slip system whose slip plane is nearly parallel to the twin boundaries of lattice invariant deformation for each habit plane variant. These slip systems correspond to the experimentally identified slip systems in the many previous studies. Based on this result, the selection of the slip system of the transformation-induced dislocations can be explained geometrically and thermodynamically as a tendency to minimize the strain energy of the system by accommodating the incompatibility in the transition layer.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"45 ","pages":"Article 102624"},"PeriodicalIF":2.9,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145885148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-17DOI: 10.1016/j.mtla.2025.102642
Borui Ren , Ye Cui , Tenglong Gong , Xiyuan Xiao , Lixin Sun , Yang Zhang , Yuxin Wu , Tan Zhao , Gang Zhao , Zhongwu Zhang
High-strength low-alloy (HSLA) steels have emerged as a candidate material in engineering applications, attributed to their balanced strength, good plasticity, and favorable weldability. However, stabilizing film-like reverse austenite (RA) at room temperature is difficult due to low alloy content of HSLA steels, which becomes a challenge to prevent the concurrent achievement of high elongation and a low yield-to-tensile ratio. In this study, a martensite-based microstructure featuring stable film-like RA and uniformly distributed Cu-rich nanoprecipitates is successfully produced in a low-alloy steel through a process involving quenching, cold rolling with 2% deformation, lamellarization, and tempering. The results reveal that 2% deformation induces dislocations, which effectively control fresh martensite (FM) with higher length-to-diameter (L/D) ratio and an initial Ni enrichment of 4.67%. Additionally, the partitioning of Ni elements during tempering creates conditions for the precipitation of uniform film-like RA. This stabilized film-like RA provides significant work-hardening capacity which enables the simultaneous achievement of high elongation (26.7%) and a low yield-to-tensile ratio (0.88) while maintaining a high yield strength of 922 MPa. This study introduces a novel strategy for developing high-performance HSLA steels, offering an effective paradigm to address the long-standing challenge of concurrently achieving high elongation and a low yield-to-tensile ratio, which are typically conflicting properties in these materials.
{"title":"A strategy for reducing yield-to-tensile ratio in HSLA steel: induced elemental partitioning to promote reverse austenite formation","authors":"Borui Ren , Ye Cui , Tenglong Gong , Xiyuan Xiao , Lixin Sun , Yang Zhang , Yuxin Wu , Tan Zhao , Gang Zhao , Zhongwu Zhang","doi":"10.1016/j.mtla.2025.102642","DOIUrl":"10.1016/j.mtla.2025.102642","url":null,"abstract":"<div><div>High-strength low-alloy (HSLA) steels have emerged as a candidate material in engineering applications, attributed to their balanced strength, good plasticity, and favorable weldability. However, stabilizing film-like reverse austenite (RA) at room temperature is difficult due to low alloy content of HSLA steels, which becomes a challenge to prevent the concurrent achievement of high elongation and a low yield-to-tensile ratio. In this study, a martensite-based microstructure featuring stable film-like RA and uniformly distributed Cu-rich nanoprecipitates is successfully produced in a low-alloy steel through a process involving quenching, cold rolling with 2% deformation, lamellarization, and tempering. The results reveal that 2% deformation induces dislocations, which effectively control fresh martensite (FM) with higher length-to-diameter (<em>L/D</em>) ratio and an initial Ni enrichment of 4.67%. Additionally, the partitioning of Ni elements during tempering creates conditions for the precipitation of uniform film-like RA. This stabilized film-like RA provides significant work-hardening capacity which enables the simultaneous achievement of high elongation (26.7%) and a low yield-to-tensile ratio (0.88) while maintaining a high yield strength of 922 MPa. This study introduces a novel strategy for developing high-performance HSLA steels, offering an effective paradigm to address the long-standing challenge of concurrently achieving high elongation and a low yield-to-tensile ratio, which are typically conflicting properties in these materials.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"45 ","pages":"Article 102642"},"PeriodicalIF":2.9,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-17DOI: 10.1016/j.mtla.2025.102640
Anis Fatehah Sa’aidi , Hussain Zuhailawati , Ahmad Farrahnoor
Traditional Ti–6Al–4V implants pose challenges due to their high stiffness and potential toxicity, prompting the development of β-type titanium (Ti) alloys with non-toxic alloying elements like niobium (Nb). Titanium hydride (TiH₂) was selected as a precursor due to its improved sinterability, oxidation resistance, and affordability. The TiH₂–Nb alloy was produced through mechanical alloying and powder metallurgy, with optimisation using the Box-Behnken Design (BBD) method. Elemental TiH₂ (60 wt%) and Nb (40 wt%) powders were milled at various speeds (100 to 300 rpm), compacted at 500 MPa, and sintered under an argon atmosphere at temperatures between 800 °C and 1200 °C for 1 to 3 h. Response surface methodology (RSM) identified sintering temperature as the most influential factor on compressive strength and elastic modulus. Optimal conditions, milling at 200 rpm and sintering at 1200 °C for 3 h, yielded in a compressive strength of 1768 MPa and an elastic modulus of 8.7 GPa, closely matching human cortical bone properties. TiH₂–Nb alloy outperformed Ti–Nb alloy in terms of densification (98.56 % relative density), reduced porosity (1.44 %), and desirability score (0.9). Thermogravimetric (TG) analysis confirmed effective dehydrogenation at higher milling speeds due to enhanced Nb diffusion and defect density. X-ray diffraction (XRD) confirmed formation of a dual-phase α+β Ti structure. Optimised TiH₂–Nb alloys offer a promising alternative to Ti–6Al–4V implants, with reduced stress shielding and improved mechanical compatibility for future orthopaedic implants.
{"title":"Optimisation of TiH2–Nb alloy for bone implant using Box–Behnken design: Enhancing strength, elastic modulus and dehydrogenation behaviour through powder metallurgy","authors":"Anis Fatehah Sa’aidi , Hussain Zuhailawati , Ahmad Farrahnoor","doi":"10.1016/j.mtla.2025.102640","DOIUrl":"10.1016/j.mtla.2025.102640","url":null,"abstract":"<div><div>Traditional Ti–6Al–4V implants pose challenges due to their high stiffness and potential toxicity, prompting the development of β-type titanium (Ti) alloys with non-toxic alloying elements like niobium (Nb). Titanium hydride (TiH₂) was selected as a precursor due to its improved sinterability, oxidation resistance, and affordability. The TiH₂–Nb alloy was produced through mechanical alloying and powder metallurgy, with optimisation using the Box-Behnken Design (BBD) method. Elemental TiH₂ (60 wt%) and Nb (40 wt%) powders were milled at various speeds (100 to 300 rpm), compacted at 500 MPa, and sintered under an argon atmosphere at temperatures between 800 °C and 1200 °C for 1 to 3 h. Response surface methodology (RSM) identified sintering temperature as the most influential factor on compressive strength and elastic modulus. Optimal conditions, milling at 200 rpm and sintering at 1200 °C for 3 h, yielded in a compressive strength of 1768 MPa and an elastic modulus of 8.7 GPa, closely matching human cortical bone properties. TiH₂–Nb alloy outperformed Ti–Nb alloy in terms of densification (98.56 % relative density), reduced porosity (1.44 %), and desirability score (0.9). Thermogravimetric (TG) analysis confirmed effective dehydrogenation at higher milling speeds due to enhanced Nb diffusion and defect density. X-ray diffraction (XRD) confirmed formation of a dual-phase α+β Ti structure. Optimised TiH₂–Nb alloys offer a promising alternative to Ti–6Al–4V implants, with reduced stress shielding and improved mechanical compatibility for future orthopaedic implants.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"45 ","pages":"Article 102640"},"PeriodicalIF":2.9,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Magnesium alloys hold immense potential for biodegradable orthopedic implants, yet their rapid degradation, coarse microstructure, and limited ductility hinder clinical translation. This study investigates a novel Mg–1.5Zn–0.5Ca alloy system modified with varying rare earth Erbium (Er) additions (0.75, 2, 5, 8 wt%) and processed through a sequential route of casting, homogenization, and symmetric hot rolling to simultaneously enhance mechanical performance, corrosion resistance, and cytocompatibility. Comprehensive characterization using SEM, EDS, XRD, and EBSD, revealed that 2 wt% Er produced the most refined microstructure, weakened basal texture and uniform W-phase dispersion. In addition, rolling significantly improved grain morphology and suppressed galvanic intermetallic networks, correlating with superior tensile properties (UTS ≈ 236 MPa, elongation ≈ 29 %) and minimized corrosion activity, as confirmed by electrochemical and immersion analyses. Moreover, SECM technique was introduced that demonstrated the lowest localized electrochemical current in 2 wt% Er alloy in rolled state, indicating stable degradation behavior. In addition cytocompatibility assessment using MC3T3-E1 cells validated cell viability above 70 %, meeting ISO 10,993–5 and USFDA standards. This integrated processing–composition approach establishes the rolled Er alloy as a promising candidate for next-generation biodegradable Mg implants, offering an optimal balance of mechanical integrity, corrosion control, and biological safety.
{"title":"Correlative investigation of microstructure, localized corrosion behavior and mechanical properties in hot rolled Mg-Zn-Ca-xEr (x = 0.75, 2, 5, 8 wt%) biodegradable alloys for orthopedic applications","authors":"Divyanshu Aggarwal , Vamsi Krishna Pakki , Sachin Latiyan , Rajesh K. Rajendran , Suraj Singh , Kapil K Gupta , Rajan Ambat , Kaushik Chatterjee , Satyam Suwas , Rajashekhara Shabadi","doi":"10.1016/j.mtla.2025.102643","DOIUrl":"10.1016/j.mtla.2025.102643","url":null,"abstract":"<div><div>Magnesium alloys hold immense potential for biodegradable orthopedic implants, yet their rapid degradation, coarse microstructure, and limited ductility hinder clinical translation. This study investigates a novel Mg–1.5Zn–0.5Ca alloy system modified with varying rare earth Erbium (Er) additions (0.75, 2, 5, 8 wt%) and processed through a sequential route of casting, homogenization, and symmetric hot rolling to simultaneously enhance mechanical performance, corrosion resistance, and cytocompatibility. Comprehensive characterization using SEM, EDS, XRD, and EBSD, revealed that 2 wt% Er produced the most refined microstructure, weakened basal texture and uniform W-phase dispersion. In addition, rolling significantly improved grain morphology and suppressed galvanic intermetallic networks, correlating with superior tensile properties (UTS ≈ 236 MPa, elongation ≈ 29 %) and minimized corrosion activity, as confirmed by electrochemical and immersion analyses. Moreover, SECM technique was introduced that demonstrated the lowest localized electrochemical current in 2 wt% Er alloy in rolled state, indicating stable degradation behavior. In addition cytocompatibility assessment using MC3T3-E1 cells validated cell viability above 70 %, meeting ISO 10,993–5 and USFDA standards. This integrated processing–composition approach establishes the rolled Er alloy as a promising candidate for next-generation biodegradable Mg implants, offering an optimal balance of mechanical integrity, corrosion control, and biological safety.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"45 ","pages":"Article 102643"},"PeriodicalIF":2.9,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145798376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-17DOI: 10.1016/j.mtla.2025.102644
Xiaoyu Wu, Wei Li, Ziheng Huang, Weitian Wang
High-entropy perovskite oxides (HEPOs) constitute a novel class of functional materials in which configurational entropy contributes to the stabilization of unique structural and functional properties. This study investigates the effect of sintering temperature (1100∼1250 °C) on the structural evolution, dielectric behavior, and impedance characteristics of a newly developed A-site quintuple-cation perovskite ceramic, (Bi0.2La0.2Ba0.2Sr0.2Ca0.2)TiO3. X-ray diffraction analysis confirms the formation of a phase-pure tetragonal structure at temperatures exceeding 1200 °C. Microstructural analysis demonstrates temperature-dependent grain growth kinetics: a rapid increase in grain size below 1200 °C (from 0.53 to 1.39 μm) is followed by entropy-suppressed coarsening, resulting in a maximum grain size of 1.50 μm at 1250 °C. This phenomenon is attributed to lattice strain induced by A-site cationic disorder. X-ray photoelectron spectroscopy verifies the presence of multivalent Ti3+/Ti4+ oxidation states and a significant concentration of oxygen vacancies, which form defect dipoles that influence polarization mechanisms. Dielectric spectroscopy reveals exceptional frequency stability within the 104–106 Hz range, with a maximum relative permittivity (ε′) of 3.05 × 105 and a low dielectric loss (tanδ) of 0.05 observed for the sample sintered at 1250 °C. Impedance spectroscopy confirms thermally activated conduction, with reduced resistance and enhanced carrier mobility at higher sintering temperatures, attributed to decreased grain boundary density and optimized defect chemistry. These findings highlight sintering temperature as a key parameter for entropy-mediated property optimization in HEPOs systems, thereby establishing (Bi0.2La0.2Ba0.2Sr0.2Ca0.2)TiO3 as a favorable combination of dielectric properties worthy of further investigation for potential use in high-stability capacitive applications.
{"title":"Effect of sintering temperature on the dielectric and impedance properties of high-entropy perovskite oxides (Bi0.2La0.2Ba0.2Sr0.2Ca0.2)TiO3","authors":"Xiaoyu Wu, Wei Li, Ziheng Huang, Weitian Wang","doi":"10.1016/j.mtla.2025.102644","DOIUrl":"10.1016/j.mtla.2025.102644","url":null,"abstract":"<div><div>High-entropy perovskite oxides (HEPOs) constitute a novel class of functional materials in which configurational entropy contributes to the stabilization of unique structural and functional properties. This study investigates the effect of sintering temperature (1100∼1250 °C) on the structural evolution, dielectric behavior, and impedance characteristics of a newly developed A-site quintuple-cation perovskite ceramic, (Bi<sub>0.2</sub>La<sub>0.2</sub>Ba<sub>0.2</sub>Sr<sub>0.2</sub>Ca<sub>0.2</sub>)TiO<sub>3</sub>. X-ray diffraction analysis confirms the formation of a phase-pure tetragonal structure at temperatures exceeding 1200 °C. Microstructural analysis demonstrates temperature-dependent grain growth kinetics: a rapid increase in grain size below 1200 °C (from 0.53 to 1.39 μm) is followed by entropy-suppressed coarsening, resulting in a maximum grain size of 1.50 μm at 1250 °C. This phenomenon is attributed to lattice strain induced by A-site cationic disorder. X-ray photoelectron spectroscopy verifies the presence of multivalent Ti<sup>3+</sup>/Ti<sup>4+</sup> oxidation states and a significant concentration of oxygen vacancies, which form defect dipoles that influence polarization mechanisms. Dielectric spectroscopy reveals exceptional frequency stability within the 10<sup>4</sup>–10<sup>6</sup> Hz range, with a maximum relative permittivity (<em>ε</em>′) of 3.05 × 10<sup>5</sup> and a low dielectric loss (tanδ) of 0.05 observed for the sample sintered at 1250 °C. Impedance spectroscopy confirms thermally activated conduction, with reduced resistance and enhanced carrier mobility at higher sintering temperatures, attributed to decreased grain boundary density and optimized defect chemistry. These findings highlight sintering temperature as a key parameter for entropy-mediated property optimization in HEPOs systems, thereby establishing (Bi<sub>0.2</sub>La<sub>0.2</sub>Ba<sub>0.2</sub>Sr<sub>0.2</sub>Ca<sub>0.2</sub>)TiO<sub>3</sub> as a favorable combination of dielectric properties worthy of further investigation for potential use in high-stability capacitive applications.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"45 ","pages":"Article 102644"},"PeriodicalIF":2.9,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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