Acta Materialia最新文献

{"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}

{"title":"Modulated clustering and precipitation in an Al–Mg–Si alloy AA 6014 via enhanced pre-aging","authors":"Meng Liu, Qianning Guo, Jingwei Zhao, Zhenshan Liu, Kaixin Chen, Yiheng Cao, Ting Chen, Feng Qian, Shiwei Pan, Xingzhong Cao, Huan Zhao, Gang Sha, Zi Yang, John Banhart, Pizhi Zhao","doi":"10.1016/j.actamat.2025.121164","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121164","url":null,"abstract":"The effect of an additional short spike aging treatment (SA: 180 to 220°C, in tens of seconds) between solution heat treatment and conventional pre-aging (PA: 85°C, in hours) on the mechanical properties of an AA 6014 alloy after paint baking was evaluated. Tensile tests show that such enhanced pre-aging including SA and PA can significantly improve the paint bake response compared to conventional pre-aging (PA only). To interpret this phenomenon, Positron Annihilation Lifetime Spectroscopy, Electrical Resistivity Measurements, Differential Scanning Calorimetry, Transmission Electron Microscopy, Atom Probe Tomography and MatCalc calculations were applied to identify the microstructural changes in different aging stages. It is found that the excess vacancies available after quenching assist in rapid nucleation of clusters during SA, which grow during subsequent PA and transform easily to β\" precipitates during paint baking owing to their similar chemistry. The densely distributed β\" precipitates are considered responsible for the improved paint bake strength as thy efficiently hinder dislocation movement.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"26 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144133737","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":"Design of superalloys with multiple properties via multi-task learning","authors":"Weiren Wang ,&nbsp;Xue Jiang ,&nbsp;Wenyao Li ,&nbsp;Chi Zhang ,&nbsp;Pei Liu ,&nbsp;Shaohan Tian ,&nbsp;Turab Lookman ,&nbsp;Yanjing Su","doi":"10.1016/j.actamat.2025.121161","DOIUrl":"10.1016/j.actamat.2025.121161","url":null,"abstract":"<div><div>The development of new materials requires the collaborative design of multiple properties, requiring an analysis of the interactions amongst material composition, processing methods, and individual properties. Traditional data-driven materials design approaches typically rely on single-task models that operate independently, often neglecting the shared insights across related tasks. To overcome this limitation, we propose a collaborative design framework that employs multi-task learning for the development of novel Co-based superalloys. In this framework, six thermodynamic and microstructural property tasks share a common encoder, which effectively captures the underlying influence of alloy compositions across different properties. Each task then utilizes its own dedicated decoder to ensure precise predictions. As a result, the average normalized error for the predictions of the six properties is reduced by 37.5 % compared to conventional single-task learning methods. Furthermore, latent high-dimensional variables are extracted from the common encoder, and utilized to identify promising exploration directions for optimal properties, as indicated by the projection of these variables, which aids in screening new alloys. We successfully designed new alloys that satisfy the targeted criteria: low density (&lt;9 g cm^-3), suitable freezing ranges (&lt;60 °C) and processing windows (&gt;80 °C), optimal γ′ sizes (&lt;550 nm after aging at 1100 °C for 168 h and &lt;200 nm after aging at 1000 °C for 24 h), high γ′ solvus temperature (&gt;1200 °C) without detrimental phases, and strong oxidation resistance. This framework represents a promising approach for collaborative materials design, leveraging shared information to enhance the development of multiple properties.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"294 ","pages":"Article 121161"},"PeriodicalIF":8.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144113792","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":"Grain boundary segregation in BCC vanadium-based alloys: Quantum-accurate computed segregation spectra and targeted experimental validations","authors":"Malik Wagih ,&nbsp;Tianjiao Lei ,&nbsp;Daniel Ng ,&nbsp;Christopher A. Schuh","doi":"10.1016/j.actamat.2025.121169","DOIUrl":"10.1016/j.actamat.2025.121169","url":null,"abstract":"<div><div>Grain boundaries are critically important to the material performance of fusion reactor materials such as vanadium, particularly mechanical properties and irradiation resistance. A key challenge to the design and control of grain boundaries in vanadium alloys is the lack of quantitative data on grain boundary segregation. In this study, we combine computational and experimental methods to address this gap. Using a machine learning-accelerated quantum mechanics/molecular mechanics approach, we calculated the segregation spectra for 28 transition metal elements in polycrystalline vanadium, and validated these predictions experimentally for a subset of solutes that sample a range of segregation behavior, specifically zirconium, titanium, and tungsten, using analytical transmission electron microscopy. The agreement between experiment and theory highlights the predictive capability of our approach. Critically, this work provides a comprehensive database of quantum-accurate solute segregation enthalpies in vanadium, enabling the development of advanced alloys for fusion reactors applications.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"294 ","pages":"Article 121169"},"PeriodicalIF":8.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144113790","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":"Ruthenium-cobalt oxide solid solution nanofiber: a robust bifunctional electrocatalyst for overall water splitting with superior ampere-grade-current-density electrocatalytic performance","authors":"Xianqiang Yu ,&nbsp;Ruikai Qi ,&nbsp;Linfeng Zhang ,&nbsp;Li Deng ,&nbsp;Mengxiao Zhong ,&nbsp;Zheng-jie Chen ,&nbsp;Xiaofeng Lu","doi":"10.1016/j.actamat.2025.121165","DOIUrl":"10.1016/j.actamat.2025.121165","url":null,"abstract":"<div><div>Constructing high-performance bifunctional electrocatalysts for water electrolysis under an ampere-grade current density is crucial for practical application. Herein, ruthenium-cobalt oxide (RuCoO_x) solid solution nanofibers (SSNFs) are fabricated as robust bifunctional electrocatalyst for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Typically, the optimized Ru₂Co₁O_x SSNFs exhibit an ultra-low overpotential of 362 mV at 1000 mA cm^-2 for OER, not only significantly superior to the prepared RuO_x nanofibers (NFs), CoO_x and commercial RuO₂ catalyst but also outperforming many reported typical OER electrocatalysts. In addition, the representative Ru₁Co₁O_x SSNFs catalyst presents a good HER performance with an overpotential of only 149 mV at 1000 mA cm^-2 and excellent stability over 120 h, surpassing the benchmark Pt/C catalyst. Furthermore, these catalysts are assembled to construct an alkaline overall water splitting cell, demonstrating a better performance than most of the recently reported water electrolyzers. Density functional theory calculations reveal that the addition of Co effectively modulates the <em>d</em>-orbitals of Ru and reduces the reaction energy barriers of O*→OOH*, benefitting to enhance the OER property. Additionally, the hybridization of Co and Ru is beneficial for modulating the strength of H* adsorption in an alkaline solution, which promotes the alkaline HER efficiency.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"294 ","pages":"Article 121165"},"PeriodicalIF":8.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144113788","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":"On the mobility of dislocations intersecting {112} free surfaces in Cu","authors":"Ta Duong ,&nbsp;Michael J. Demkowicz","doi":"10.1016/j.actamat.2025.121170","DOIUrl":"10.1016/j.actamat.2025.121170","url":null,"abstract":"<div><div>We perform atomistic simulations to study the motion of edge dislocations intersecting {112} free surfaces in Cu. For dislocations of length &gt; 11 nm, intersections with the free surface exert a drag force that reduces mobility. This force increases with velocity and appears to diverge below the Rayleigh wave speed (<span><math><mrow><msub><mi>c</mi><mi>R</mi></msub><mrow><mo>)</mo></mrow></mrow></math></span>. New dislocations emitted from the surface effectively prevent the intersections from exceeding <span><math><msub><mi>c</mi><mi>R</mi></msub></math></span>. For line lengths equal to or below 11 nm, dislocations additionally excite Lamb (bending) waves in the medium. Resonances with these waves generate new subsonic branches in the stress-velocity relation, giving rise to intermittent fluctuations in dislocation velocity at constant imposed strain rate. These findings exhibit qualitative differences to the behavior of dislocations under periodic boundaries, suggesting that experiments measuring mobilities from the displacements of dislocation intersections with free surfaces may not fully represent the behavior of dislocations within crystal interiors, especially at near-sonic velocities and above.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"295 ","pages":"Article 121170"},"PeriodicalIF":8.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144113791","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":"Understanding the synergistic Co-Mo effect in maraging steels: redistribution of solute atoms","authors":"Jong-Kwan Lee,&nbsp;Seon-Gyu Kim,&nbsp;Donghwa Lee,&nbsp;Byeong-Joo Lee","doi":"10.1016/j.actamat.2025.121171","DOIUrl":"10.1016/j.actamat.2025.121171","url":null,"abstract":"<div><div>Maraging steels achieve ultrahigh strength through precipitation hardening using intermetallic compounds. In these steels, Co enhances strength by promoting the precipitation of Mo-based intermetallic compounds. This phenomenon, known as the synergistic Co-Mo effect, is the key factor for their exceptional strength. However, the underlying mechanism of this synergistic effect remains unclear. In this study, to determine the cause of the synergistic Co-Mo effect, we investigated the redistribution of solute atoms using atomistic Monte Carlo (MC) simulations. Specifically, we developed neural network potentials tailored for this study and employed them in the MC simulations. Our simulations revealed that the co-addition of Co and Mo resulted in compositional separation into Mo-rich/Co-lean and Mo-lean/Co-rich regions, which we propose as the cause for the synergistic Co-Mo effect. Furthermore, we confirmed that this compositional separation is closely related to interactions among solute atoms.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"294 ","pages":"Article 121171"},"PeriodicalIF":8.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144113789","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":"Diffusion mechanism of Zr-4 alloy at ultra-low temperature based on the α→β phase transition promoted by thermo-hydrogen treatment","authors":"Yingkai Ma ,&nbsp;Qing Chang ,&nbsp;Hairui Ding ,&nbsp;Zhan Sun ,&nbsp;Xinrui Guo ,&nbsp;Weimin Long ,&nbsp;Zhenwen Yang ,&nbsp;Ying Wang ,&nbsp;Lixia Zhang","doi":"10.1016/j.actamat.2025.121156","DOIUrl":"10.1016/j.actamat.2025.121156","url":null,"abstract":"<div><div>To achieve low-temperature robust diffusion bonding of Zr-4 alloys, thermo-hydrogen treatment (THT) has been conducted prior to the bonding process. After the THT, the bonding temperature can be reduced by 100 °C (achieving the same bonding strength of 200 MPa). The typical microstructure of hydrogenated Zr-4 alloy at room temperature was composed of precipitated hydrides (γ-ZrH, δ-ZrH_1.66, ε-ZrH₂) and α-Zr matrix. The in-situ XRD results at 550 °C∼700 °C indicated that the γ-ZrH δ-ZrH_1.66, and ε-ZrH₂ decreased gradually, the ζ-ZrH_0.25 and β_H-Zr formed with the rising temperature. DSC data indicated that the α→β phase transition temperature was decreased from 825 °C to 550 °C after the Zr-4 alloy was subjected to THT. According to the molecular dynamics (MD) results, the diffusion coefficient of Zr atoms in the β-Zr lattice was 1.36 × 10^–6 nm²·ps^-1 which was much higher than that in the α-Zr lattice (2.24 × 10^–8 nm²·ps^-1). After the phase transition, the vacancy and interstitial diffusion formation energy significantly reduced from 2.61 eV and 3.67 eV to -0.6 eV and -1.0 eV, corresponding to the abundant defects as shown in-situ TEM images of β (β_H) at 650 °C. The vacancy and interstitial diffusion activation energy of Zr atoms in β_H-Zr lattices were reduced from 3.22 eV and 3.92 eV to 1.3 eV and 0.1 eV. Thus, the hydrogen-induced phase transition and the formation of the β_H-Zr phase were confirmed as the key factors in achieving low-temperature diffusion bonding of Zr-4 alloys.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"294 ","pages":"Article 121156"},"PeriodicalIF":8.3,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144113343","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":"Structure-to-process modeling drives experimentally validated unified dual-phase steel","authors":"Xudong Ma ,&nbsp;Yuqi Zhang ,&nbsp;Chenchong Wang ,&nbsp;Ming Wang ,&nbsp;Mingxin Huang ,&nbsp;Wei Xu","doi":"10.1016/j.actamat.2025.121167","DOIUrl":"10.1016/j.actamat.2025.121167","url":null,"abstract":"<div><div>Unified dual-phase (UniDP) steels enable tailored performance from a single composition, revolutionizing sustainable material systems by addressing recyclability and weldability challenges. Traditional design frameworks, constrained by forward \"process-structure\" models and costly uncertainty quantification, falter under sparse data and complex microstructures. Here, a microstructure-centric inverse design strategy is proposed that replaces uncertainty quantification with direct \"structure-to-composition/process modeling\", leveraging real microstructural features to map composition and processing parameters. Specifically, our approach integrates a variational autoencoder to encode authentic microstructural features into a latent space and a multilayer perceptron to predict composition, processing routes, and properties. Combined with specific latent space sampling, the framework achieves high-efficacy design exploration. The experimental success of UniDP steels stands as a cornerstone of this work: the designed alloy consistently achieves the target properties in all three performance tiers, at a lower cost than other commercial alloys. Latent space analysis further validated the model's ability to interpolate seamlessly between microstructures and encode multi-scale property relationships, confirming its robustness for real-world applications. By experimentally demonstrating the viability of microstructure-driven inverse design, this work not only resolves longstanding barriers in complex alloy systems but also establishes a replicable, uncertainty quantification-free framework for sustainable material innovation.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"295 ","pages":"Article 121167"},"PeriodicalIF":8.3,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144113793","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}