Acta Materialia最新文献

{"title":"Extraordinary strength-ductility synergy in superalloy joints via a high-entropy-alloy modified multi-interlayer composite bonding strategy","authors":"L. Yuan ,&nbsp;Y.Z. Yang ,&nbsp;J. Gan ,&nbsp;T.H. Chou ,&nbsp;Y.M. Zhao ,&nbsp;D. Hao ,&nbsp;J.Y. Zhang ,&nbsp;J.L. Li ,&nbsp;J.T. Xiong ,&nbsp;T. Yang","doi":"10.1016/j.actamat.2025.121186","DOIUrl":"10.1016/j.actamat.2025.121186","url":null,"abstract":"<div><div>Diffusion bonding with innovative interlayers is critical for manufacturing high-precision aerospace turbine components requiring exceptional comprehensive performances, yet achieving simultaneous strength and ductility in superalloy bonding joints remains challenging. Developing high-performance interlayer material, introducing effective strengthening strategies, and elucidating deformation mechanisms in the superalloy joints can address this issue. This study introduces a multi-interlayer composite bonding technique using a “BNi2/high entropy alloy/BNi2” sandwich structured interlayer to join powder metallurgy superalloy FGH98. The liquid BNi2 interlayer eliminated interfacial defects, reducing the risk of a brittle fracture at the interface. The high entropy alloy interlayer of FeCoNiTiAl promoted atomic diffusion between the interlayer and base metals, facilitating the in situ formation of TiB₂ borides, M₃B₂ borides, γ' nanoparticles and comprising distinct zones with different deformation capabilities. This heterogeneous joint microstructure resulted in an extraordinary strength-ductility synergy through strain partitioning and load transfer. Among these zones, the strengthening effect in the Ti-boride zone (TBZ) with in situ TiB₂ borides was crucial, particularly at elevated temperatures. High work-hardening and deformation capabilities were attributed to TiB₂’s effectiveness in obstructing dislocation movement and generating stacking faults within the borides. As a result, an ultrahigh ultimate tensile strength of 1410 ± 10 MPa, a total elongation at fracture of 19 ± 0.5 % at room temperature, and a maximum tensile strength of 981 ± 20 MPa at 800 °C were achieved in the bonding joint.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"295 ","pages":"Article 121186"},"PeriodicalIF":8.3,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-temperature stability of Hf0.5Zr0.5O2-based ferroelectric memory devices","authors":"Hongdi Wu ,&nbsp;Boxu Yan ,&nbsp;Gang Bai ,&nbsp;Wenbin Tang ,&nbsp;Guodong Zhang ,&nbsp;Yecheng Ding ,&nbsp;Xubing Lu ,&nbsp;Zhibo Yan ,&nbsp;Jun-Ming Liu ,&nbsp;Guoliang Yuan","doi":"10.1016/j.actamat.2025.121179","DOIUrl":"10.1016/j.actamat.2025.121179","url":null,"abstract":"<div><div>The rapid development of high-temperature electronic devices requires new memory devices capable of read and write operations at high-temperature for approximately billion cycles. In this study, we explored the failure mechanism of the ferroelectric memory device with W/Hf_0.5Zr_0.5O₂/W structure and significantly improved its high-temperature stability during write/read cycles even at 200 °C. The generation of new oxygen vacancies during polarization switching process led to the significant increase in the leakage current and final electric breakdown. The leakage current after 10⁹ write/read cycles decreased by &gt;99.998 % at 200 °C when a zero-electric-field rest time of 2 μs was integrated between the two pulsed electric fields. Consequently, the maximum write/read cycles increased from 7.2 × 10⁸ to 1.4 × 10¹⁰ at 200 °C, demonstrating excellent high-temperature stability. These findings provide a basis for further developing high-density ferroelectric memory devices with ultra-fast read-write capabilities and outstanding high-temperature stability.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"294 ","pages":"Article 121179"},"PeriodicalIF":8.3,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144145593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Erratum to “Deformation Twinning in a Refractory High Entropy Alloy with B2-ordered Crystal Structure” [AM 290 (2025) 120926]","authors":"Oleg N. Senkov, Bryan J. Crossman, Michael J. Mills","doi":"10.1016/j.actamat.2025.121150","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121150","url":null,"abstract":"The publisher regrets of errors the publisher made during formatting equations in the referenced manuscript. Incorrectly formatted <span><span>Equations (2)</span></span>, <span><span>(3)</span></span>, <span><span>(4)</span></span>, <span><span>(5)</span></span> <span><span>(8)</span></span> and <span><span>(10)</span></span> should be replaced with those shown below:","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"24 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144145831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tuning anisotropic grain growth and high-temperature deformation in TiAl alloys via directional annealing: role of hot zone migration rate and 3D twin networks","authors":"Zedong Liu, Jieren Yang, Yunlu Ma, Na Jin, Ying Liu, Ruirun Chen","doi":"10.1016/j.actamat.2025.121181","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121181","url":null,"abstract":"Directional solidification enables fabrication of polysynthetically twinned (PST) TiAl alloys with superior mechanical properties; yet persistent challenges in industrial scalability and process stability hinder practical implementation. This work demonstrates crucible-free processing of columnar-grained/single-crystal TiAl alloys through solid-state directional heat treatment, proposing a novel pathway for industrial production of high-performance intermetallics. Through advanced multi-scale microstructural characterization and in situ grain boundary (GB) tracking, we reveal that reduced hot zone (HZ) migration rates (&lt;span&gt;&lt;span style=\"\"&gt;&lt;math&gt;&lt;msub is=\"true\"&gt;&lt;mi is=\"true\"&gt;V&lt;/mi&gt;&lt;mtext is=\"true\"&gt;thermal&lt;/mtext&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;&lt;span style=\"font-size: 90%; display: inline-block;\" tabindex=\"0\"&gt;&lt;svg focusable=\"false\" height=\"2.317ex\" role=\"img\" style=\"vertical-align: -0.582ex;\" viewbox=\"0 -747.2 3084.5 997.6\" width=\"7.164ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"&gt;&lt;g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"&gt;&lt;g is=\"true\"&gt;&lt;g is=\"true\"&gt;&lt;use xlink:href=\"#MJMATHI-56\"&gt;&lt;/use&gt;&lt;/g&gt;&lt;g is=\"true\" transform=\"translate(583,-150)\"&gt;&lt;use transform=\"scale(0.707)\" xlink:href=\"#MJMAIN-74\"&gt;&lt;/use&gt;&lt;use transform=\"scale(0.707)\" x=\"389\" xlink:href=\"#MJMAIN-68\" y=\"0\"&gt;&lt;/use&gt;&lt;use transform=\"scale(0.707)\" x=\"946\" xlink:href=\"#MJMAIN-65\" y=\"0\"&gt;&lt;/use&gt;&lt;use transform=\"scale(0.707)\" x=\"1390\" xlink:href=\"#MJMAIN-72\" y=\"0\"&gt;&lt;/use&gt;&lt;use transform=\"scale(0.707)\" x=\"1783\" xlink:href=\"#MJMAIN-6D\" y=\"0\"&gt;&lt;/use&gt;&lt;use transform=\"scale(0.707)\" x=\"2616\" xlink:href=\"#MJMAIN-61\" y=\"0\"&gt;&lt;/use&gt;&lt;use transform=\"scale(0.707)\" x=\"3117\" xlink:href=\"#MJMAIN-6C\" y=\"0\"&gt;&lt;/use&gt;&lt;/g&gt;&lt;/g&gt;&lt;/g&gt;&lt;/svg&gt;&lt;/span&gt;&lt;script type=\"math/mml\"&gt;&lt;math&gt;&lt;msub is=\"true\"&gt;&lt;mi is=\"true\"&gt;V&lt;/mi&gt;&lt;mtext is=\"true\"&gt;thermal&lt;/mtext&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/script&gt;&lt;/span&gt;=2 μms&lt;sup&gt;-1&lt;/sup&gt;) enhance α-GB mobility via curvature-driven dynamics, with the disparity in migration rates across the double GB junctions being compensated by the formation of GB coupling steps, producing columnar structures with 38.8 mm length and aspect ratios exceeding unity. Conversely, accelerated &lt;span&gt;&lt;span style=\"\"&gt;&lt;math&gt;&lt;msub is=\"true\"&gt;&lt;mi is=\"true\"&gt;V&lt;/mi&gt;&lt;mtext is=\"true\"&gt;thermal&lt;/mtext&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;&lt;span style=\"font-size: 90%; display: inline-block;\" tabindex=\"0\"&gt;&lt;/span&gt;&lt;script type=\"math/mml\"&gt;&lt;math&gt;&lt;msub is=\"true\"&gt;&lt;mi is=\"true\"&gt;V&lt;/mi&gt;&lt;mtext is=\"true\"&gt;thermal&lt;/mtext&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/script&gt;&lt;/span&gt; (8 μms&lt;sup&gt;-1&lt;/sup&gt;) refine α&lt;sub&gt;2&lt;/sub&gt;/γ lamellar spacing by 90.8 %, elevating 900°C tensile strength by 87.4 MPa but compromising ductility by 48.1 %. The remarkable ductility observed at 2 μms&lt;sup&gt;-1&lt;/sup&gt; is attributed to a three-dimensional twin network within the γ lamellae (γ&lt;sub&gt;L&lt;/sub&gt;), which is maintained by secondary twinning at stress-concentrated interfaces. These findings establish quantitative relationships between thermal processing parameters, GB kinetics, and deformation mechanisms, offering cri","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"40 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144145833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fundamental study to grow single crystals with high performances operated up to high temperatures in donor-doped materials for energy harvesting","authors":"Su-Jin Ha ,&nbsp;Young Kook Moon ,&nbsp;Hyun-Ae Cha ,&nbsp;Jong-Jin Choi ,&nbsp;Byung-Dong Hahn ,&nbsp;Seong-Hui Choi ,&nbsp;Il-Ryeol Yoo ,&nbsp;Kyung-Hoon Cho ,&nbsp;Kyoung-Seok Moon ,&nbsp;Cheol-Woo Ahn","doi":"10.1016/j.actamat.2025.121180","DOIUrl":"10.1016/j.actamat.2025.121180","url":null,"abstract":"<div><div>An energy-harvesting material with high energy-conversion constant (d₃₃ × g₃₃) and Curie temperature (T_C) is required to effectively harvest the mechanical energy which has not been recycled into electrical energy. Here, we present an eco-friendly single-crystals, the 3rd generation material, for energy harvesting with the excellent d₃₃ × g₃₃ of 118 10^–12 m²N^-1 (d₃₃=1030 pCN^-1) and high T_C of 390 °C, prepared by simple heat-treatment. A donor (not an acceptor) has been doped to (K,Na)NbO₃ (KNN)-based materials to obtain single-crystals through exceptionally abnormal grain growth (AGG). The severe AGG in a donor-doped KNN is explained by the donor effect to locally accelerate the volatilization of metals earlier. In particular, a donor-doped PbTiO₃ (PT + Bi³⁺) material as well as a donor-doped KNN material allows for the synthesis of a single-crystal seed through the simple molten salt method. These findings advance understanding of sintering mechanisms in metal-volatile oxides and offer significant progress in energy-harvesting materials.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"295 ","pages":"Article 121180"},"PeriodicalIF":8.3,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144145830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electro-chemo-mechanical behavior of a layered cathode material upon cycling","authors":"Robert Löser, Yug Joshi, Roham Talei, Petra Ebbinghaus, Guido Schmitz","doi":"10.1016/j.actamat.2025.121155","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121155","url":null,"abstract":"The mechanical characteristics of lithium-ion cathode materials plays a critical role in determining battery performance such as durability, cycle life, and safety, especially when the battery is under external pressure which is typical for all-solid-state batteries. This study focuses on LiCoO₂ (LCO), a widely used hexagonal layer-structured cathode material for lithium-ion batteries, and investigates its mechanical properties during de-/lithiation using sputter-deposited thin films and nanoindentation. The values of the experimental Young’s modulus in pure (101) and (003) lattice orientations are quantified to 337.1 <span><math><mo is=\"true\">±</mo></math></span> 8.7 GPa and 267.9 <span><math><mo is=\"true\">±</mo></math></span> 7.2 GPa, respectively, in the fully lithiated state. Furthermore, a substantial texture-dependent decrease in Young’s modulus upon lithium deintercalation is demonstrated, probably due to modification of the bonding interactions between the cobalt oxide layers. The decrease of Li content also elevates the relative contribution of plastic deformation, indicating that dislocation glide becomes easier in deintercalated states. By extensive cycling, the Young’s modulus in higher lithiated charge-states decreases considerably which is most-likely due to irreversibility of phase transitions. In contrast, the material shows a significant increase of plastic hardness with cycling, understood as work hardening. The work provides valuable insight on the dynamic changes of the mechanical properties during electrochemical cycling of LiCoO₂, which paves the way for all other layered cathode materials.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"56 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144133650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Elucidating the microstructure evolution during hydrogen-based direct reduction via a case study of single crystal hematite","authors":"Barak Ratzker ,&nbsp;Martina Ruffino ,&nbsp;Shiv Shankar ,&nbsp;Dierk Raabe ,&nbsp;Yan Ma","doi":"10.1016/j.actamat.2025.121174","DOIUrl":"10.1016/j.actamat.2025.121174","url":null,"abstract":"<div><div>Sustainable hydrogen-based direct reduction (HyDR) of iron oxide is an effective approach to reduce carbon emissions in steel production. As the reduction behaviour is closely related to the microstructure evolution, it is important to understand the microscopic reduction mechanisms. Industrial hematite pellets are microstructurally intricate systems with inherent porosity, defects, and impurities. Therefore, in the present study we investigated the HyDR of single crystal hematite (at 700 °C) to elucidate the reduction behaviour and microstructure evolution in a model system. The reduction kinetics of the single crystal (SC) were compared to those of industrial polycrystalline porous pellets using thermogravimetric analysis. Additional SC samples were prepared such that their faces are parallel to the (0001), (<span><math><mrow><mn>10</mn><mover><mn>1</mn><mo>¯</mo></mover><mn>0</mn></mrow></math></span>) and (<span><math><mrow><mn>1</mn><mover><mn>2</mn><mo>¯</mo></mover><mn>10</mn></mrow></math></span>) crystallographic planes of hematite, and then partially reduced to 16 and 80 % reduction degree. Their microstructure was thoroughly examined by scanning electron microscopy and electron backscatter diffraction (EBSD). Reaction fronts were thus shown to advance into the hematite by a shrinking core model while creating a percolating pore network in the magnetite layer; this was closely followed by wüstite and iron formation, as well as pore coarsening, with the retained oxides proceeding to reduce homogenously throughout the sample abiding by the pore/grain models. Notably, a “cell-like” morphology develops in the magnetite near the hematite/magnetite interface, with finely porous “cell interiors” surrounded by coarsely porous “cell walls”. Furthermore, the hierarchal pore formation, phase transformations, texture, and orientation relationships are considered.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"294 ","pages":"Article 121174"},"PeriodicalIF":8.3,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144130389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functionally Graded NiTiHf High-Temperature Shape Memory Alloys Using Laser Powder Bed Fusion: Localized Phase Transformation Control and Multi-Stage Actuation","authors":"Abdelrahman Elsayed, Taresh Guleria, Haoyi Tian, Bibhu P. Sahu, Kadri C. Atli, Alaa Olleak, Alaa Elwany, Raymundo Arroyave, Dimitris Lagoudas, Ibrahim Karaman","doi":"10.1016/j.actamat.2025.121175","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121175","url":null,"abstract":"This study presents the successful additive manufacturing of functionally graded (FG) NiTiHf high-temperature shape memory alloys using Laser Powder Bed Fusion. A novel approach was implemented to achieve precise voxel-level control of local chemistry and microstructure starting from a single feedstock composition, enabling location-specific phase transformation characteristics. By systematically analyzing the relationships between volumetric energy density, Ni evaporation, and transformation temperatures, the study achieved accurate control of Ni content across different segments of the functionally graded materials (FGMs). Thermal modeling further elucidated the influence of thermal history change, due to changes in the process parameters and sample size, on Ni evaporation and oxide formation, findings that were experimentally validated by local transmission electron microscopy analyses. Wavelength dispersive spectroscopy confirmed the localized control of Ni content, while differential scanning calorimetry identified multiple transformation peaks in the FG NiTiHf samples, indicating multi-stage transformation behavior throughout the FG segments. The transformation range spanned over 150°C, demonstrating the capability to engineer tailored thermomechanical responses across different regions within the printed components. A novel thermomechanical modeling approach effectively predicted the global actuation response of the FG parts, and mechanical testing demonstrated broader transformation ranges and high strain recovery in the samples. These results highlight the potential of FG HTSMAs for applications requiring tailored actuation and reliable performance across varying high-temperature ranges, offering a viable path forward for enhancing their high-temperature functionality.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"59 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144133649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Introducing strain glass transition into high-entropy TiZrHfNiCuCo alloys exhibiting elastocaloric effect and quasi-linear superelasticity","authors":"Kaichao Zhang ,&nbsp;Chao Lv ,&nbsp;Guanqi Li ,&nbsp;Zeyi Li ,&nbsp;Xueyi Huo ,&nbsp;Zhuangweici Sun ,&nbsp;Zhengrui Li ,&nbsp;Changshuo Zhang ,&nbsp;Jiaxing Zheng ,&nbsp;Kai Wang ,&nbsp;Yulin Chen ,&nbsp;Xinqing Zhao ,&nbsp;Huilong Hou","doi":"10.1016/j.actamat.2025.121172","DOIUrl":"10.1016/j.actamat.2025.121172","url":null,"abstract":"<div><div>High entropy alloys (HEAs) have garnered significant attention due to their vast compositional space and tremendous potential for advanced structural and functional properties. While most studies on HEAs concentrate on optimizing one or two primary characteristics, there exists a transformative opportunity in designing HEAs that integrate multiple structural and functional attributes. In this work, we present equiatomic TiZrHfNiCuCo HEAs that exhibit a remarkable combination of mechanical and functional properties, including high strength, low elastic modulus, quasi-linear superelasticity, broad-temperature-range elastocaloric effect with a high coefficient of performance (<span><math><mrow><mi>C</mi><mi>O</mi><msub><mi>P</mi><mtext>material</mtext></msub></mrow></math></span>) spanning from 223 K to 423 K, elastic modulus softening, and exceptional fatigue stability exceeding 10⁵ cycles. Through detailed nanoscale microstructural analysis, we demonstrate that these properties are linked to the strain glass transition in the HEAs, characterized by frequency-dependent modulus behavior, invariance of average structure, non-ergodicity, and the formation and growth of nanodomains. The high <span><math><mrow><mi>C</mi><mi>O</mi><msub><mi>P</mi><mtext>material</mtext></msub></mrow></math></span> elastocaloric effect, and long-term fatigue stability can be attributed to the quasi-linear superelasticity with narrow hysteresis that originates from the stress-induced continuous evolution of nanodomains. The elastic modulus softening arises from the combined contributions of the elastic modulus softening of the B2 matrix and the elastic modulus hardening of B19′ and R nanodomains, as well as other precipitates. Our work sheds light on the strategy to introduce strain glass transition into advanced HEAs for designing structural and functional properties.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"294 ","pages":"Article 121172"},"PeriodicalIF":8.3,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144122474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Growth crystallography and in-situ imaging of nucleation and growth dynamics of Al8Mn5 solidifying in AZ magnesium alloys","authors":"D. Wang, G. Zeng, J.W. Xian, K. Nogita, H. Yasuda, C.M. Gourlay","doi":"10.1016/j.actamat.2025.121168","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121168","url":null,"abstract":"Many magnesium-aluminium-based alloys contain a small manganese addition to improve corrosion resistance. However, this introduces Al-Mn intermetallics which add complexity to the phase transformations. Here we study the crystal growth of the most common Al-Mn phase, Al₈Mn₅, in Mg-Al-Zn-Mn-based magnesium alloy solidification by combining electron microscopy of the faceted growth crystallography with in-situ synchrotron X-ray imaging of the Al₈Mn₅ nucleation and growth dynamics. Three Al₈Mn₅ morphologies, equiaxed, rod and plate, are shown to all come from cyclic twinned growth associated with the pseudo-cubic symmetry of rhombohedral Al₈Mn₅. X-ray imaging revealed Al₈Mn₅ nucleated throughout the freezing range and grew with α-Mg dendrites over a wide temperature range by divorced eutectic solidification. This occurs because, in these alloys, Mn solute has little influence on the solute undercooling of growing α-Mg dendrites, although strongly affects the constitutional supercooling with respect to the Al₈Mn₅ liquidus. Rod/plate growth of Al₈Mn₅ is shown to be promoted by slow cooling rates and by divorced eutectic solidification. The findings provide new insights into the conditions that cause large, deleterious rods and plates, and explain why there is a large variation in Al₈Mn₅ growth morphology after solidification.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"93 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144130447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}