Acta Materialia最新文献

{"title":"Crystal plasticity parameter identification via statistical relevant micropillar compression","authors":"Niklas C. Fehlemann ,&nbsp;Angelica Medina ,&nbsp;Subin Lee ,&nbsp;Christoph Kirchlechner ,&nbsp;Sebastian Münstermann","doi":"10.1016/j.actamat.2025.121321","DOIUrl":"10.1016/j.actamat.2025.121321","url":null,"abstract":"<div><div>In order to predict ductile damage initiation at the microstructure level, especially for multi-phase materials, it is essential to have high-fidelity crystal plasticity parameters. They need to accurately represent the evolving phase contrast, which implies that the initial phase contrast and the individual strain hardening of the phases has to be mapped precisely. This paper presents a methodology for calibrating the parameters of a phenomenological crystal plasticity model for a DP800 steel based on the critical resolved shear stress from <em>in situ</em> micropillar compression tests taken out of macroscopic tensile tests at various prestrain levels. Furthermore, the influence of mechanical size effects was incorporated through the inclusion of statistical relevant micropillar compression tests of varying prestrains and dimensions. The data were used to calibrate a model, which successfully predicted the homogenized macroscopic stress–strain curve from uniaxial tensile tests with a mean absolute error of only <span><math><mrow><mn>20</mn><mo>.</mo><mn>7</mn><mo>±</mo><mn>7</mn><mo>.</mo><mn>7</mn><mspace></mspace><mi>MPa</mi></mrow></math></span> and a mean absolute percentage error of 3.3%. Furthermore, it was shown that the influence of the strain hardening of the martensite can be neglected under certain conditions, especially when predicting the homogenized stress response for low strains. This result demonstrates the importance of high-fidelity parameter calibration for damage prediction, when compared to a synthetic parameter set, which leads to a different stress and strain partitioning for the same homogenized stress–strain curve.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"297 ","pages":"Article 121321"},"PeriodicalIF":8.3,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144679644","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":"Micro-alloying-driven Transformation Mechanisms of T1p to T1 in Al-Cu-Li-Mg-Ag Alloys","authors":"Lipeng Ding, Flemming J.H. Ehlers, Qingbo Yang, Yaoyao Weng, Suya Liu, Chenglin Wang, Qing Liu, Zhihong Jia","doi":"10.1016/j.actamat.2025.121371","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121371","url":null,"abstract":"This study presents an atomistic experimental and theoretical investigation into the different stages of evolution from the early T_1p phase to fully matured T₁ in an Al-Cu-Li-Mg-Ag alloy, with the central aim of clarifying the role of the micro-alloying elements Mg and Ag in the T_1p → T₁ transformation. In addition to the heterogeneous nucleation of the T₁ precipitate on pre-existing dislocations, the present work provides direct experimental support for homogeneous T_1p nucleation, with transformation into T₁ proceeding via a distinct pathway involving nucleation of dislocation loops or antiparallel pairs within T_1p, independent of pre-existing dislocations. Contrasting earlier conclusions, the T_1p → T₁ transformation is found to initiate with an atomic rearrangement within the T_1p Al-Cu layers into Kagomé nets (“Al-Cu layer reorientation”), with Shockley partial dislocations (SPDs) activation and passage following only after this point. This structural transformation order is explained by the Kagomé nets introducing structural geometries promoting the SPD activation. Li and Mg at the interface are identified as primary contributors to the SPD passage-induced transformation driving force. Ag complements this process indirectly by facilitating Li incorporation. The final stages of transformation are diffusion-limited, with Cu and Li incorporation representing the slowest step. These results substantiate atomistically the role of the micro-alloying elements Mg and Ag in homogeneous T_1p nucleation and transformation.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"111 3S 1","pages":"121371"},"PeriodicalIF":9.4,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144684587","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":"Creep-induced microstructures in Zircaloy-4: comparing thermal and irradiation creep","authors":"Ronit Roy, Fei Long, Brodie Moore, Mark R. Daymond","doi":"10.1016/j.actamat.2025.121370","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121370","url":null,"abstract":"Irradiation creep is one of the most critical deformation mechanisms observed in nuclear reactor components, which results in a significant shape change during the service period. In irradiation creep, the magnitude of the shape change is typically significantly higher than under thermal creep under comparable stresses and temperatures. Hence, it is essential to consider the effect of irradiation creep for the safe and economical operation of nuclear reactors. Although numerous works have been conducted to understand the irradiation creep behaviour, many aspects are still not fully understood. The present study explores the irradiation creep behaviour using a multiscale characterization approach by combining high-resolution electron backscatter diffraction and transmission electron microscopy analysis. The microstructure that has evolved during irradiation creep is compared with two thermal creep examples, with our analysis considering the residual elastic strains, GND densities, and dislocation (also irradiation defect) microstructures. It is observed that the irradiation creep is driven by both diffusion- and dislocation-based mechanisms, with a significant diffusion creep component, owing to the radiation-enhanced diffusion rate and the abundant number of point defects produced during irradiation. On pyramidal traces, numerous localized concentrations are observed in GND density and residual strain maps, resulting from the cross-slip of dislocations and the remanent debris accumulated through the process. 3D tomography analysis further reveals the dislocation creep mechanism in Zr alloys, where &lt;a&gt; dislocations emerge as small dislocation loops on pyramidal planes and multiply through cross-slip.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"14 1","pages":"121370"},"PeriodicalIF":9.4,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144685079","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":"Efficient stainless steel-based bifunctional water electrolysis electrode: Activating the OPM mechanism in OER and enhancing HER performance","authors":"Chengzhen Hou ,&nbsp;Lu Xue ,&nbsp;Lingyan Zhou ,&nbsp;Chao Chen ,&nbsp;Xuewei Lv ,&nbsp;Jie Dang","doi":"10.1016/j.actamat.2025.121361","DOIUrl":"10.1016/j.actamat.2025.121361","url":null,"abstract":"<div><div>Low-cost, resource-rich and efficient bifunctional catalysts play a crucial role in advancing hydrogen production and its applications. In this study, based on inexpensive and readily available stainless steel materials, we designed and synthesized an efficient and cost-effective stainless steel-based bifunctional water electrolysis electrode (Ru-PSS) through a coupling interface and doping strategy. Specifically, at a current density of 500 mA∙cm^-2, the electrode exhibited a hydrogen evolution reaction (HER) overpotential of just 248 mV and an oxygen evolution reaction (OER) overpotential of only 353 mV. Notably, a symmetrical anion exchange membrane (AEM) electrolyser assembled with Ru-PSS electrodes can achieve an industrial high current density of 500 mA∙cm^-2 at a low voltage of only 1.82 V. In situ electrochemical Fourier transform infrared spectroscopy (FTIR) experiments further indicate that the electrode involves the adsorption evolution mechanism (AEM) and oxide pathway mechanism (OPM), both of which jointly promote oxygen evolution reaction. Comprehensive material characterization and density-functional theory (DFT) indicate that in situ phosphorylation synthesizes heterostructures (FeP₄/Ni₂P) on the stainless steel surface, providing abundant active sites for catalytic reactions. Subsequently, trace Ru doping (Ru-FeP₄/Ni₂P) not only significantly improves the HER performance by optimizing the free energy of hydrogen adsorption (ΔG_H*), but also activates a more catalytically active OPM reaction mechanism by modulating the electronic structure. This study provides innovative design ideas and theoretical guidance for the development of highly efficient and stable new steel-based catalysts for water electrolysis.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"297 ","pages":"Article 121361"},"PeriodicalIF":8.3,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670085","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":"Kinked basal dislocation loops for anomalous annealing hardening in irradiated zirconium","authors":"Si-Mian Liu, Shi-Hao Zhang, Hiroaki Abe, Shigenobu Ogata, Wei-Zhong Han","doi":"10.1016/j.actamat.2025.121366","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121366","url":null,"abstract":"Annealing is a traditional pathway to mitigate irradiation hardening in metals, while an anomalous annealing hardening is widely observed in neutron-irradiated zirconium (Zr), which is counterintuitive and intriguing, and affects the performance of Zr components in nuclear reactors. Here, we report that the anomalous annealing hardening in irradiated Zr originates from thermally activated formation of three-dimensional kinked &lt;c&gt; dislocation loops. Through concurrent in-situ heating experiments inside a transmission electron microscope, we demonstrate that irradiation-induced planar &lt;c&gt; dislocation loops progressively merge into zigzag-shape kinked configurations between 400°C -500°C. Atomistic simulations reveal that partial dislocations generated by the dissociation of 1/6&lt;2<span><span style=\"\"></span><span data-mathml='&lt;math xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mover accent=\"true\" is=\"true\"&gt;&lt;mn is=\"true\"&gt;2&lt;/mn&gt;&lt;mo is=\"true\"&gt;&amp;#xAF;&lt;/mo&gt;&lt;/mover&gt;&lt;/math&gt;' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"2.202ex\" role=\"img\" style=\"vertical-align: -0.235ex;\" viewbox=\"0 -846.5 570.5 947.9\" width=\"1.325ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><g is=\"true\" transform=\"translate(35,0)\"><use xlink:href=\"#MJMAIN-32\"></use></g><g is=\"true\" transform=\"translate(0,198)\"><use x=\"-70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use><use x=\"70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use></g></g></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mover accent=\"true\" is=\"true\"><mn is=\"true\">2</mn><mo is=\"true\">¯</mo></mover></math></span></span><script type=\"math/mml\"><math><mover accent=\"true\" is=\"true\"><mn is=\"true\">2</mn><mo is=\"true\">¯</mo></mover></math></script></span>03&gt; loops glide on pyramidal planes driven by the inter-loop attraction forces, ultimately forming kinked steps. These three-dimensional kinked &lt;c&gt; loops act as strong obstacles for prismatic &lt;a&gt; dislocations, leading to a pronounced hardening. This discovery provides a universal framework for understanding the annealing-induced hardening in hexagonal close-packed metals.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"659 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144664365","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":"Atomic distribution of alloying elements and second phase particles (SPPs) identification in Optimised ZIRLO","authors":"Siyu Huang ,&nbsp;Levi Tegg ,&nbsp;Sima Aminorroaya Yamini ,&nbsp;Lucia Chen ,&nbsp;Patrick Burr ,&nbsp;Jiangtao Qu ,&nbsp;Limei Yang ,&nbsp;Ingrid McCarroll ,&nbsp;Julie M. Cairney","doi":"10.1016/j.actamat.2025.121365","DOIUrl":"10.1016/j.actamat.2025.121365","url":null,"abstract":"<div><div>The accurate chemical composition of second phase particles (SPPs) and solute distributions at grain boundaries and interfaces are still not known for Optimised ZIRLO, with recent debate over the identification of a Zr-Nb-Fe intermetallic phase in these alloys. Here, atom probe tomography (APT) is combined with scanning transmission electron microscopy (STEM), transmission Kikuchi diffraction (TKD), and density functional theory (DFT) to demonstrate that the phase, commonly reported as Zr(Nb,Fe)₂, is most likely an intermetallic phase of (Zr,Nb)₃Fe with ∼35 at.% Nb.</div><div>Interfacial excess is calculated at the β-Nb/α-Zr and (Zr,Nb)₃Fe/α-Zr interfaces and at the grain boundaries. Fe is enriched at the interface between β-Nb precipitates and the α-Zr matrix. Fe, Sn, and Nb segregate at α-Zr grain boundaries, no Sn segregation was observed at the interface of β-Nb/α-Zr matrix, and slight Sn segregation was detected at the interface of the intermetallic phases with the α-Zr and at the grain boundaries.</div><div>An enhanced understanding of grain boundary segregation, secondary phases composition, and solute behaviour will inform a better understanding of mechanical and corrosion properties, which is expected to be useful for future Zr alloy development.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"297 ","pages":"Article 121365"},"PeriodicalIF":8.3,"publicationDate":"2025-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144664364","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":"Effects of HCP elements Ti and Zr on the plastic deformation behavior of Ti-Zr-Nb medium-entropy alloys with the BCC structure","authors":"Shu Han, Zhi Wang, Le Li, Shohei Onda, Zhenghao Chen, Jean-Philippe Couzinié, Haruyuki Inui","doi":"10.1016/j.actamat.2025.121367","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121367","url":null,"abstract":"The deformation behavior of Ti-Zr-Nb medium-entropy alloys (MEAs) with the body-centered cubic (BCC) structure has been investigated as a function of the HCP (hexagonal close-packed)-element (Ti and Zr) concentration in compression at temperatures between 50 and 1173 K and is discussed in terms of the extent of lattice distortion quantified as mean-square atomic displacement (MSAD). The temperature dependence of yield stress observed for all the Ti-Zr-Nb MEAs investigated is essentially the same as that observed for conventional BCC metals and alloys, featuring a rapid decrease at low temperatures (<ce:italic>T</ce:italic>&lt;<ce:italic>T<ce:inf loc=\"post\">1</ce:inf></ce:italic>), a plateau at intermediate temperatures (<ce:italic>T<ce:inf loc=\"post\">1</ce:inf></ce:italic>≤<ce:italic>T</ce:italic>&lt;<ce:italic>T<ce:inf loc=\"post\">2</ce:inf></ce:italic>) and a rapid decrease again at higher temperatures (<ce:italic>T</ce:italic>≥<ce:italic>T<ce:inf loc=\"post\">2</ce:inf></ce:italic>). The deformation mechanism is converted from the Peierls mechanism at low temperatures (<ce:italic>T</ce:italic>&lt;<ce:italic>T<ce:inf loc=\"post\">1</ce:inf></ce:italic>) to an athermal process involving local pinning of screw dislocations at superjogs presumably by solute cluster arising from non-random distributions of the constituent elements at plateau temperatures (<ce:italic>T<ce:inf loc=\"post\">1</ce:inf></ce:italic>≤<ce:italic>T</ce:italic>&lt;<ce:italic>T<ce:inf loc=\"post\">2</ce:inf></ce:italic>), as evidenced by the arc-shaped configurations of screw dislocations bowing-out between pinning points. The extent of lattice distortion (MSAD) increases with higher HCP-element concentration and enhances the resistance to dislocation motion, thereby raising both the thermal stress at 0 K and the athermal stress (i.e., the plateau stress). The increased lattice distortion also leads to the steeper temperature dependence of yield stress at low temperatures (<ce:italic>T</ce:italic>&lt;<ce:italic>T<ce:inf loc=\"post\">1</ce:inf></ce:italic>) resulting in the lower onset temperature (<ce:italic>T<ce:inf loc=\"post\">1</ce:inf></ce:italic>) for the plateau.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"660 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144664962","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":"Screening high-entropy dopants to modulate microstructure of high-nickel layer cathodes for overcoming fast Li+ kinetics-stable structure trade-off","authors":"Xiaoling Cui ,&nbsp;Chengyu Li ,&nbsp;Ningshuang Zhang ,&nbsp;Jiawen Zhang ,&nbsp;Hao Ding ,&nbsp;Shiyou Li ,&nbsp;Peng Wang ,&nbsp;Dongni Zhao","doi":"10.1016/j.actamat.2025.121362","DOIUrl":"10.1016/j.actamat.2025.121362","url":null,"abstract":"<div><div>The intrinsic structural instability brings challenge for the high-nickel layered oxide cathode to break the trade-off between high rate capacity and cycle stability. Here, we screen out four doping elements (Al, Mg, Zr, Zn) based on the formation energy, and successfully synthesize a novel high-entropy cathode of LiNi_0.8Mn_0.1Co_0.02Cr_0.02Mg_0.02Zn_0.02Al_0.02O₂ (HEO<img>CMZA). Due to the Ni-site substitution of multi-dopants, HEO<img>CMZA achieves the highest configurational entropy, ensuring structural stability during the long-term cycling. In-situ characterizations and theoretical calculations furtherly verify that the high-entropy doping tailors the lattice structure, which radially stretches the Li unit cell while compresses the Ni unit cell, thereby enlarging the Li⁺ diffusion channel in the Li layer and increasing the Ni²⁺ migration energy barriers in the transition metal (TM) layer. Therefore, the high-entropy-triggered lattice distortion effect and sluggish diffusion effect not only accelerate Li⁺ diffusion but also suppress phase transition. In addition, the cocktail effect of high-entropy dopants increases the area of “Fermi Sea”, enhancing the electronic conductivity, as well as pins the TM-O, mitigating the O₂ release and microcracks. Consequently, benefitted from the synchronous enhancements of the structural strength and Li⁺ diffusion kinetics, the HEO<img>CMZA battery exhibits a remarkable cycle stability (remaining 85.88 % after 200 cycles at 1 C), the distinguished rate capability (10 C, 136.7 mAh <em>g</em>⁻¹), especially the superior capacity retention (77.03 %, 100 cycles) at 10 C, outperformed other doped counterparts reported to date. This proposed strategy of applying high-entropy effects to modulate the microstructure provides an insightful guidance in the design of high-energy-density battery materials.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"297 ","pages":"Article 121362"},"PeriodicalIF":8.3,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144664366","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":"Stereological description of grain boundary driving and resisting pressures -Solution to the Smith/Zener model","authors":"Burton R. Patterson, Yixiong Liu","doi":"10.1016/j.actamat.2025.121360","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121360","url":null,"abstract":"This paper presents a model for predicting second phase pinned grain size using a ratio of simple stereological terms- the length of grain boundary-second phase triple-line, <ce:italic>L<ce:inf loc=\"post\">V</ce:inf></ce:italic>, per grain boundary area, <mml:math altimg=\"si20.svg\"><mml:mrow><mml:mspace width=\"0.33em\"></mml:mspace><mml:msubsup><mml:mi>S</mml:mi><mml:mi>V</mml:mi><mml:mi>g</mml:mi></mml:msubsup></mml:mrow></mml:math>. This pinning potential <ce:italic>Z = L<ce:inf loc=\"post\">V</ce:inf> /</ce:italic><mml:math altimg=\"si20.svg\"><mml:mrow><mml:mspace width=\"0.33em\"></mml:mspace><mml:msubsup><mml:mi>S</mml:mi><mml:mi>V</mml:mi><mml:mi>g</mml:mi></mml:msubsup><mml:mspace width=\"0.33em\"></mml:mspace></mml:mrow></mml:math>= <ce:italic>P<ce:inf loc=\"post\">A</ce:inf> /</ce:italic><mml:math altimg=\"si21.svg\"><mml:mrow><mml:mspace width=\"0.33em\"></mml:mspace><mml:msubsup><mml:mi>P</mml:mi><mml:mi>L</mml:mi><mml:mi>g</mml:mi></mml:msubsup></mml:mrow></mml:math> is straightforward to measure from counting triple points, <ce:italic>P<ce:inf loc=\"post\">A,</ce:inf></ce:italic> and test line intercepts <mml:math altimg=\"si21.svg\"><mml:mrow><mml:mspace width=\"0.33em\"></mml:mspace><mml:msubsup><mml:mi>P</mml:mi><mml:mi>L</mml:mi><mml:mi>g</mml:mi></mml:msubsup></mml:mrow></mml:math> on the section plane. The measure of triple line per boundary area is the quantity Smith/Zener sought to quantify indirectly in their <ce:italic>f/r</ce:italic> model, these direct measurements not being available at the time. The above expression for <ce:italic>Z</ce:italic> encompasses the generally overlooked degree of non-random contact between the grain boundary and second phase, <ce:italic>R</ce:italic>. The final predictive model includes the stereologically measured boundary curvature<mml:math altimg=\"si22.svg\"><mml:mrow><mml:mo>,</mml:mo><mml:mspace width=\"0.33em\"></mml:mspace><mml:mover accent=\"true\"><mml:mi>H</mml:mi><mml:mo>¯</mml:mo></mml:mover></mml:mrow></mml:math>, that drives grain growth, which Smith/Zener approximated as inverse grain size. These terms, which are easier to measure experimentally than <ce:italic>f</ce:italic> and <ce:italic>r</ce:italic>, were found to exert far greater effect on pinned grain size than the specific formulation of <ce:italic>Z</ce:italic> that has been the focus of many prior models. Testing was performed on sintered alumina with three levels of MgO doping causing widely different levels of grain boundary curvature and contact. Using this model the predicted grain sizes for this large variation in pinning conditions condensed to a single trend within experimental measurement error of the actual pinned grain size.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"659 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144664785","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":"Automatic intelligent multiscale simulation to predict mechanical properties and deformation mechanism of complex concentrated alloys","authors":"Baobin Xie, Yang Chen, Bin Liu, Qihong Fang, Peter K Liaw, Jia Li","doi":"10.1016/j.actamat.2025.121359","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121359","url":null,"abstract":"Due to differences in atomic interactions, chemical heterogeneous structures are inevitably formed, especially in complex concentrated alloys, which strongly influences their mechanical behaviors and properties. However, existing continuum mechanics models fail to consider key mechanical information on characteristics of atoms themselves and their interactions, and simultaneously bridge discrete atomic scale with continuum scale remains a great challenge. Here, we propose a general automatic multiscale simulation framework that integrates the approach of machine learning, atomic simulation, dislocation dynamics, crystal plasticity finite element method, and constitutive model for bridging from atomic discrete mechanics to continuum mechanics. The proposed framework mainly focuses on dual physical scales: (i) discrete atomic configuration-dependent nanoscale atomic-level strain tensor, and (ii) continuum theory-based deformation behavior and macroscopic mechanical response. To quantitatively describe atomic-strain-field constrained dislocation behavior, automatic workflow is developed for mesoscale strain field. The atomic discrete scale and dislocation continuum scale are seamlessly connected through simulation framework, enabling overall computational scheme of simultaneously dealing with atomistic effects and mesoscale dislocation movement. The atomic information-guided, machine learning-enabled automatic multiscale simulation is applied to complex concentrated alloys, which achieves an automated and intelligent prediction from atomic structure characteristics to macroscopic mechanical properties and plastic deformation mechanisms. The findings indicate that increasing chemical heterogeneous significantly enhances strain amplitude while broadening the spacing between strain peaks/valleys, resulting in a competition between hardening driven by dislocation cross-slip and softening caused by dislocation motion. The proposed automatic multiscale simulation framework not only creates a bridge between discrete mechanics and continuum mechanics, but also would be extended to other metal systems.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"14 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144664786","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}