Pub Date : 2026-01-02DOI: 10.1016/j.mtla.2026.102649
Limeng Yin , Zilong Su , Hong Jiang , Yaoning Sun , Long Zhang , Yong Yin , Yuhua Chen , Wei Feng , Danni Song
Cu/Sn/Cu sandwich structure with asymmetric double interfaces was fabricated via electromagnetic pulse welding technology. The interface waveform formation is attributed to the coupling mechanism of fluid dynamics, material plastic instability, and energy dissipation. At the Cu flyer/Sn interface, localized melting induced by rapid local heating, followed by ultrafast cooling, facilitated efficient liquid-phase diffusion. This promoted the formation of a two-phase mixed intermetallic compound layer (Cu6Sn5 and Cu3Sn), confirming metallurgical bonding. Conversely, at the Cu substrate/Sn interface, energy dissipation constrains kinetic/thermal energy input and limits the diffusion to the solid-state regime, which is dominated by short-range diffusion at the grain boundary. Consequently, only steady-state Cu3Sn developed under high-pressure conditions.
{"title":"Double interface bonding mechanism of Cu/Sn/Cu sandwich structure by electromagnetic pulse welding","authors":"Limeng Yin , Zilong Su , Hong Jiang , Yaoning Sun , Long Zhang , Yong Yin , Yuhua Chen , Wei Feng , Danni Song","doi":"10.1016/j.mtla.2026.102649","DOIUrl":"10.1016/j.mtla.2026.102649","url":null,"abstract":"<div><div>Cu/Sn/Cu sandwich structure with asymmetric double interfaces was fabricated via electromagnetic pulse welding technology. The interface waveform formation is attributed to the coupling mechanism of fluid dynamics, material plastic instability, and energy dissipation. At the Cu flyer/Sn interface, localized melting induced by rapid local heating, followed by ultrafast cooling, facilitated efficient liquid-phase diffusion. This promoted the formation of a two-phase mixed intermetallic compound layer (Cu<sub>6</sub>Sn<sub>5</sub> and Cu<sub>3</sub>Sn), confirming metallurgical bonding. Conversely, at the Cu substrate/Sn interface, energy dissipation constrains kinetic/thermal energy input and limits the diffusion to the solid-state regime, which is dominated by short-range diffusion at the grain boundary. Consequently, only steady-state Cu<sub>3</sub>Sn developed under high-pressure conditions.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"45 ","pages":"Article 102649"},"PeriodicalIF":2.9,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939201","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 : 2026-01-02DOI: 10.1016/j.mtla.2026.102651
Stephen D. Funni , Peter Ercius , Sebastian Calderon , Elizabeth C. Dickey
Many members of the tetragonal tungsten bronze (TTB) family of oxides display an incommensurate periodic lattice distortion, the nature of which has been the subject of some controversy. Here we present a study of this structural modulation in the relaxor ferroelectric Ba5SmSn3Nb7O30 (BSSN) by quantitative scanning transmission electron microscopy (STEM). We characterize the modulation in BSSN by employing a fast, pixelated direct electron detector to perform high resolution phase contrast STEM imaging of the crystalline lattice. By quantitatively analyzing the images, we visualize the atomic structural correlations present in the material on both the cation and anion sublattices. This analysis reveals the incommensurate structure to have an octahedral tilting pattern and cooperative A2 site cation displacements, analogous to an Ama2 commensurate cell. Finally, we show that the modulation is composed of a structural motif with a period of 3 x and modified by discommensurations, likely arise from frustrated octahedral tilting in the odd-valued periodicity.
四方钨青铜（TTB）氧化物家族的许多成员表现出不相称的周期性晶格畸变，其性质一直是一些争议的主题。本文用定量扫描透射电子显微镜（STEM）研究了弛豫铁电体Ba5SmSn3Nb7O30 （BSSN）的这种结构调制。我们通过采用快速、像素化的直接电子探测器对晶格进行高分辨率相对比STEM成像来表征BSSN中的调制。通过定量分析图像，我们可视化了材料中正离子和阴离子亚晶格上存在的原子结构相关性。这种分析揭示了不相称的结构具有八面体倾斜模式和协同A2位点阳离子位移，类似于Ama2相称细胞。最后，我们证明了调制是由一个周期为3 x d11¯0的结构基元组成的，并被可能由奇值周期中受挫的八面体倾斜引起的失调所修正。
{"title":"The incommensurate modulation of tetragonal tungsten bronze quantified by high resolution 4D STEM","authors":"Stephen D. Funni , Peter Ercius , Sebastian Calderon , Elizabeth C. Dickey","doi":"10.1016/j.mtla.2026.102651","DOIUrl":"10.1016/j.mtla.2026.102651","url":null,"abstract":"<div><div>Many members of the tetragonal tungsten bronze (TTB) family of oxides display an incommensurate periodic lattice distortion, the nature of which has been the subject of some controversy. Here we present a study of this structural modulation in the relaxor ferroelectric Ba<sub>5</sub>SmSn<sub>3</sub>Nb<sub>7</sub>O<sub>30</sub> (BSSN) by quantitative scanning transmission electron microscopy (STEM). We characterize the modulation in BSSN by employing a fast, pixelated direct electron detector to perform high resolution phase contrast STEM imaging of the crystalline lattice. By quantitatively analyzing the images, we visualize the atomic structural correlations present in the material on both the cation and anion sublattices. This analysis reveals the incommensurate structure to have an octahedral tilting pattern and cooperative A2 site cation displacements, analogous to an <em>Ama2</em> commensurate cell. Finally, we show that the modulation is composed of a structural motif with a period of 3 x <span><math><msub><mi>d</mi><mrow><mn>1</mn><mover><mn>1</mn><mo>¯</mo></mover><mn>0</mn></mrow></msub></math></span> and modified by discommensurations, likely arise from frustrated octahedral tilting in the odd-valued periodicity.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"45 ","pages":"Article 102651"},"PeriodicalIF":2.9,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939103","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 : 2026-01-02DOI: 10.1016/j.mtla.2026.102652
Kaichi Saito , Yuga Okamoto , Yuichiro Hayasaka
The development of high-performance Cu–Ti alloys like Cu–4 at.% Ti has been hindered because their discontinuous precipitation (DP) mechanism remains unclear. In this study, the isothermal aging behaviors of three Cu–Ti alloys, including two where Zr was partially substituted for Ti, were compared. The precipitation behavior characteristics of Zr-containing alloys were determined using advanced electron microscopy. At 450 °C, the age-hardening behaviors of the supersaturated solid solution alloys with or without Zr were initially similar, with peaks at ∼10 h. Thereafter, the Zr-containing alloys exhibited reduced age-softening behaviors. Unlike binary Cu–4Ti, ternary Cu–3.9Ti–0.1Zr exhibited no DP up to 100 h and retained high tensile strength and fracture elongation comparable to those at 10 h. Atomic-scale scanning transmission electron microscopy imaging combined with energy-dispersive X-ray spectroscopy analysis revealed that the ternary alloy had its grain boundaries decorated by the preferentially segregated Zr solutes, leading to an amorphous local atomic structure. The effects of Zr-doping on the microstructural evolution of Cu–Ti alloys were elucidated, and the local structural environment responsible for the enhanced mechanical performance was clarified.
{"title":"Inhibitory effect of Zr-doping on discontinuous precipitation in an age-hardenable Cu–Ti alloy","authors":"Kaichi Saito , Yuga Okamoto , Yuichiro Hayasaka","doi":"10.1016/j.mtla.2026.102652","DOIUrl":"10.1016/j.mtla.2026.102652","url":null,"abstract":"<div><div>The development of high-performance Cu–Ti alloys like Cu–4 at.% Ti has been hindered because their discontinuous precipitation (DP) mechanism remains unclear. In this study, the isothermal aging behaviors of three Cu–Ti alloys, including two where Zr was partially substituted for Ti, were compared. The precipitation behavior characteristics of Zr-containing alloys were determined using advanced electron microscopy. At 450 °C, the age-hardening behaviors of the supersaturated solid solution alloys with or without Zr were initially similar, with peaks at ∼10 h. Thereafter, the Zr-containing alloys exhibited reduced age-softening behaviors. Unlike binary Cu–4Ti, ternary Cu–3.9Ti–0.1Zr exhibited no DP up to 100 h and retained high tensile strength and fracture elongation comparable to those at 10 h. Atomic-scale scanning transmission electron microscopy imaging combined with energy-dispersive X-ray spectroscopy analysis revealed that the ternary alloy had its grain boundaries decorated by the preferentially segregated Zr solutes, leading to an amorphous local atomic structure. The effects of Zr-doping on the microstructural evolution of Cu–Ti alloys were elucidated, and the local structural environment responsible for the enhanced mechanical performance was clarified.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"45 ","pages":"Article 102652"},"PeriodicalIF":2.9,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939203","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 : 2026-01-02DOI: 10.1016/j.mtla.2026.102650
Muhammad Akmal, Jenniffer Bustillos, Mahya Azizi, Atieh Moridi
Additive manufacturing (AM) can enable novel alloy design by merging multiple commercial alloys into a single build, a concept we term alloy amalgamation. Here, we demonstrate how directed energy deposition (DED) of Ti-5553 and Ti-6Al-4V in equal proportions produces a chemically and structurally heterogeneous microstructure comprising both arguably hard (α, α′) and ductile (metastable β, α″) phases, all derived from the high-temperature β phase. Regions associated with metastable β and α″ underwent transformation and twinning under stress, respectively, consequently showing enhanced strain hardening. Phase analysis of samples under tensile testing revealed martensite and nano-domain (O’ and O’’) formation in β regions, followed by twinning and slip in harder phases at higher stresses. These cooperative mechanisms yielded a synergistic strength–ductility balance, with ultimate tensile strength comparable to Ti-6Al-4V and elongation approaching Ti-5553. Such exclusive trait combinations arose from localized compositional gradients and multiphase stabilization enabled by AM
{"title":"Alloy amalgamation via additive manufacturing for phase and deformation engineering in titanium alloys","authors":"Muhammad Akmal, Jenniffer Bustillos, Mahya Azizi, Atieh Moridi","doi":"10.1016/j.mtla.2026.102650","DOIUrl":"10.1016/j.mtla.2026.102650","url":null,"abstract":"<div><div>Additive manufacturing (AM) can enable novel alloy design by merging multiple commercial alloys into a single build, a concept we term alloy amalgamation. Here, we demonstrate how directed energy deposition (DED) of Ti-5553 and Ti-6Al-4V in equal proportions produces a chemically and structurally heterogeneous microstructure comprising both arguably hard (α, α′) and ductile (metastable β, α″) phases, all derived from the high-temperature β phase. Regions associated with metastable β and α″ underwent transformation and twinning under stress, respectively, consequently showing enhanced strain hardening. Phase analysis of samples under tensile testing revealed martensite and nano-domain (O’ and O’’) formation in β regions, followed by twinning and slip in harder phases at higher stresses. These cooperative mechanisms yielded a synergistic strength–ductility balance, with ultimate tensile strength comparable to Ti-6Al-4V and elongation approaching Ti-5553. Such exclusive trait combinations arose from localized compositional gradients and multiphase stabilization enabled by AM</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"45 ","pages":"Article 102650"},"PeriodicalIF":2.9,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939104","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.2025.102648
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}
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 : 2025-12-18DOI: 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}
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