Acta Materialia最新文献

{"title":"Phase-boundary assisted flash sintering of Al2O3-TiO2 nanocomposites","authors":"Shiyu Zhou ,&nbsp;Chao Shen ,&nbsp;David Estrella ,&nbsp;Alfredo Sanjuan ,&nbsp;Huan Li ,&nbsp;Yifan Zhang ,&nbsp;Chang Liu ,&nbsp;Danny Hermawan ,&nbsp;Ke Xu ,&nbsp;Zhongyujie Liu ,&nbsp;Benson Kunhung Tsai ,&nbsp;Jialong Huang ,&nbsp;Xuanyu Sheng ,&nbsp;Abhijeet Choudhury ,&nbsp;Yang Chen ,&nbsp;R. Edwin García ,&nbsp;Xinghang Zhang ,&nbsp;Haiyan Wang","doi":"10.1016/j.actamat.2025.121612","DOIUrl":"10.1016/j.actamat.2025.121612","url":null,"abstract":"<div><div>Al₂O₃ is inherently challenging to flash sinter due to its highly insulating nature. In contrast, TiO₂ can be flash sintered readily due to its better electrical and ionic conductivity at elevated temperatures than those of Al₂O₃. In this study, two-phase composites of Al₂O₃-TiO₂ with various molar ratios (i.e., 34 mol.% Al₂O₃/66 mol.% TiO₂ and 20 mol.% Al₂O₃/80 mol.% TiO₂) have been successfully processed by flash sintering and a systematic flash sintering map has been constructed to explore the relationship between electric field (ranging from 300 to 1600 V/cm) and the flash sintering temperature in Al₂O₃-TiO₂ composites. The map clearly demonstrates that the flash sintering temperature of composites decreases with increasing electric field or higher TiO₂ molar ratio. The potential mechanisms of phase boundary assisted flash sintering are discussed. This study confirms that the appropriate design of two-phase composites can prominently promote the flash sintering of insulating ceramic materials.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"302 ","pages":"Article 121612"},"PeriodicalIF":9.3,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145229331","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":"Taming cyclic reliability in high-strength Al alloys via gradient subgrain-nanoprecipitate composite structures","authors":"Dongfan Zhu ,&nbsp;Xiaoyuan Yuan ,&nbsp;Weifeng He ,&nbsp;Sihai Luo ,&nbsp;Hui Wang ,&nbsp;Hongen Chen ,&nbsp;Gang Liu ,&nbsp;Zhaoping Lu","doi":"10.1016/j.actamat.2025.121611","DOIUrl":"10.1016/j.actamat.2025.121611","url":null,"abstract":"<div><div>Cyclic reliability, a key indicator of a material’s mechanical stability under cyclic loading, is inherently tied to fatigue performance. Precipitation-strengthened high-strength Al alloys typically undergo significant cyclic softening under asymmetric stress cycles with a positive mean stress, thereby inducing premature fatigue failure. Here, we report a high-strength Al alloy engineered with a dual-gradient architecture, featuring both subgrains and nanoprecipitates, which displays remarkable resistance to cyclic softening, resulting in a nearly two-order-of-magnitude enhancement in fatigue life. This superior cyclic stability stems from the rapid dynamic hardening response and high mechanical energy dissipation intrinsic to this gradient subgrain-nanoprecipitate structure. Specifically, the synergistic interaction between the subgrain network and graded precipitate distribution reconfigures dislocation behavior from cross-slip to planar slip, while fragmenting dislocations into fine slip units. These unique interactions facilitate stable cyclic hardening and high internal damping. Consequently, strain localization is effectively suppressed, and both crack initiation and propagation are significantly delayed. This composite gradient strategy provides a novel paradigm for designing fatigue-resistant Al alloys.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"301 ","pages":"Article 121611"},"PeriodicalIF":9.3,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145229330","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":"Mitigating delayed fracture in AlSi-coated 2 GPa press-hardened steel via surface plasticity-induced hydrogen delocalization","authors":"M. Guan ,&nbsp;J.Y. Zhang ,&nbsp;Z. Wang ,&nbsp;Z.H. Cao ,&nbsp;Z. Dong ,&nbsp;B.B. He ,&nbsp;M.X. Huang","doi":"10.1016/j.actamat.2025.121614","DOIUrl":"10.1016/j.actamat.2025.121614","url":null,"abstract":"<div><div>AlSi-coated 2 GPa press-hardened steel (PHS) has great potential for improving fuel efficiency in the automotive industry owing to its ultra-high strength. However, the ultra-high strength increases the hydrogen embrittlement risks and thus hinders its broad application. To mitigate its hydrogen embrittlement risks, a novel mechanism that is surface plasticity-induced hydrogen delocalization is proposed. While the conventional surface structure of industrial PHS composed of brittle intermetallics and interdiffusion ferrite (IF), exhibits negligible plasticity during the bending test, the newly developed PHS features a surface structure composed of ductile low-Al/Si IF, thereby activating substantial surface plasticity capable of enhanced plastic deformation energy storage. The enhanced surface plasticity enables the elimination of pre-existing cracks during thermal processing, coordinating multiple mechanisms including blunting of crack tip, expansion of plastic zone, twisting of crack propagation path, and the multiplication of hydrogen trapping sites in the surface structure during bending fracture. Consequently, both stress and hydrogen concentration near the main crack are noticeably alleviated, thereby mitigating the hydrogen embrittlement risks. Experiment results demonstrate that the hydrogen embrittlement resistance of the newly developed PHS is improved by more than twofold without sacrificing the tensile properties. This work provides a new pathway to mitigate the HE risks of 2 GPa AlSi-coated PHS and promotes its application in the automotive industry.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"301 ","pages":"Article 121614"},"PeriodicalIF":9.3,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145235122","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":"Interface morphology and dislocation-mediated processes during rapid solidification of thin films","authors":"Sammohith Nittala ,&nbsp;Jaarli Suviranta ,&nbsp;Tatu Pinomaa ,&nbsp;Thomas Voisin ,&nbsp;Duncan Burns ,&nbsp;Joseph T. McKeown ,&nbsp;Anssi Laukkanen ,&nbsp;Nikolas Provatas","doi":"10.1016/j.actamat.2025.121581","DOIUrl":"10.1016/j.actamat.2025.121581","url":null,"abstract":"<div><div>Rapid solidification experiments have, in recent years, revealed a wealth of new microstructural phenomena that suggest a strong connection between the kinetics of solidification and the crystalline structures that emerge as a result. In this work, we investigate the interplay between interface morphology and defect-mediated processes during rapid solidification conditions using a Phase Field Crystal (PFC) model, enabling us to simultaneously and efficiently explore the physics of solidification and elasto-plasticity in the formalism of a single-field theory. We predict that there are two mechanisms by which dislocations emitted directly from the solid–liquid interface induce orientation gradients as well as the formation of subgrain boundaries within a single solidifying cell. We relate these mechanisms to the morphology of the moving solid–liquid interface and identify a suitable control parameter in the PFC model with which we can go between said morphologies by effectively changing the relative strength of the capillary length and kinetic coefficients of the solid–liquid interface. Thus, we are able to provide mechanistic explanations for several microstructural features (with an emphasis on orientation gradients and subgrain boundaries) observed during the rapid solidification of pure materials. We also provide a simple explanation for the formation of “jagged” subgrain boundaries, which is consistent with our experimental observations in rapidly solidified samples of Aluminum, whose mechanisms have thus far been unknown.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"302 ","pages":"Article 121581"},"PeriodicalIF":9.3,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226700","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":"Spatiotemporal microstructure evolution during martensitic transformation in titanium alloys using deep learning","authors":"Bangtan Zong ,&nbsp;Jinshan Li ,&nbsp;Ping Wang ,&nbsp;Weijie Liao ,&nbsp;Turab Lookman ,&nbsp;Ruihao Yuan","doi":"10.1016/j.actamat.2025.121603","DOIUrl":"10.1016/j.actamat.2025.121603","url":null,"abstract":"<div><div>We address the issue of accuracy and efficiency (speed) in phase field simulations of titanium alloys using heterogeneous microstructures via deep learning based surrogate models. A data set with 124 groups of 3D images (<span><math><mo>∼</mo></math></span>320,000 2D images) is first assembled via high throughput phase field simulations by varying the interfacial mobility and interfacial energy. The data is used to train surrogate models to “learn” the spatiotemporal evolution of microstructures. These models predict images over a wide time span by learning from the same number of images from the previous time interval. This also holds when the model learns from images obtained using a low interfacial mobility parameter to predict images with high mobility. Moreover, compared to the typical long short-term memory neural network designed for sequential data, the proposed model shows advantages in both accuracy and efficiency, in predictions of images far from those used in training. Specifically, for predicting the image at 4000th evolved time step, the mean squared error based on pixel value is reduced from 0.2755 to 0.065 (a 76.4% reduction) while the prediction time required is only 1/15, i.e., reduced from 5.11 s to 0.38 s. The work sheds light on the use of deep learning tools to accelerate materials simulations without sacrificing accuracy.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"301 ","pages":"Article 121603"},"PeriodicalIF":9.3,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226698","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":"Shear-activated phase transformations of diborides via machine-learning potential molecular dynamics","authors":"Shuyao Lin ,&nbsp;David Holec ,&nbsp;Davide G. Sangiovanni ,&nbsp;Thomas Leiner ,&nbsp;Lars Hultman ,&nbsp;Paul H. Mayrhofer ,&nbsp;Nikola Koutná","doi":"10.1016/j.actamat.2025.121606","DOIUrl":"10.1016/j.actamat.2025.121606","url":null,"abstract":"<div><div>The layered character of transition metal diborides (TMB₂:s)—with three structure polymorphs representing different stackings of the metallic sublattice—evokes the possibility of activating phase-transformation plasticity via mechanical shear strain. This is critical to overcome the most severe limitation of TMB₂:s: their brittleness. To understand finite-temperature mechanical response of the <span><math><mi>α</mi></math></span>, <span><math><mi>ω</mi></math></span>, and <span><math><mi>γ</mi></math></span> polymorphs at the atomic scale, we train machine-learning interatomic potentials (MLIPs) for TMB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>:s, TM <span><math><mo>=</mo></math></span> (Ti, Ta, W, Re). Validation against <em>ab initio</em> data set supports the MLIPs’ capability to predict structural and elastic properties, as well as shear-induced slipping and phase transformations. Nanoscale molecular dynamics simulations (<span><math><mrow><mo>&gt;</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>4</mn></mrow></msup></mrow></math></span> atoms; <span><math><mrow><mo>≈</mo><msup><mrow><mn>5</mn></mrow><mrow><mn>3</mn></mrow></msup><mspace></mspace><msup><mrow><mi>nm</mi></mrow><mrow><mn>3</mn></mrow></msup></mrow></math></span>) allow evaluating theoretical shear strengths attainable in single-crystal TMB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>:s and their temperature evolution from 300 up to 1200 K. Quantitative structural analysis via angular and bond-order Steinhardt parameter descriptors shows that <span><math><mrow><mrow><mo>(</mo><mn>0001</mn><mo>)</mo></mrow><mrow><mo>[</mo><mover><mrow><mn>1</mn></mrow><mo>¯</mo></mover><mn>2</mn><mover><mrow><mn>1</mn></mrow><mo>¯</mo></mover><mn>0</mn><mo>]</mo></mrow></mrow></math></span> and <span><math><mrow><mrow><mo>(</mo><mn>0001</mn><mo>)</mo></mrow><mrow><mo>[</mo><mn>10</mn><mover><mrow><mn>1</mn></mrow><mo>¯</mo></mover><mn>0</mn><mo>]</mo></mrow></mrow></math></span> shearing activates transformations between the (energetically) metastable and the preferred phase of TiB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, TaB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, and WB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>. These transformations can be promoted by additional tensile or compressive strain along the [0001] axis. The preferred phase of ReB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> shows negative thermal expansion and an unprecedented shear-induced plasticity mechanism: metallic/boron layer interpenetration and uniform lattice rotation.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"301 ","pages":"Article 121606"},"PeriodicalIF":9.3,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226706","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":"Probing the mechanisms of morphological evolution and phase selection of intermetallic compounds for impurity-tolerant processing of recycled Al alloys","authors":"Shikang Feng ,&nbsp;Mika Shearwood ,&nbsp;Andrew Lui ,&nbsp;Dominic Banks ,&nbsp;Tim Nicholls ,&nbsp;Sion Richards ,&nbsp;Matthew D. Wilson ,&nbsp;Patrick S. Grant ,&nbsp;Enzo Liotti","doi":"10.1016/j.actamat.2025.121591","DOIUrl":"10.1016/j.actamat.2025.121591","url":null,"abstract":"<div><div>Fe-rich intermetallic compounds (IMCs) are a persistent challenge in the recirculation of secondary aluminium alloys. Despite significant research effort, largely via post-solidification studies, the mechanisms governing IMC phase selection in higher-Fe (<span><math><mrow><mo>&gt;</mo><mn>1</mn></mrow></math></span> wt.%), recycled Al alloys and how they can be controlled to facilitate more benign IMC species and/or morphologies remain poorly understood. This creates barriers to compositional and process design for more Fe-tolerant alloys. In this paper, we present a systematic real-time investigation of IMC formation, phase selection and morphological evolution in recycled 3xx series Al alloys with elevated Fe concentrations (up to 2.5 wt%), using <em>in situ</em> synchrotron X-ray radiography. Coupled with thermodynamic simulations, we develop a method to reliably estimate the formation temperatures of primary <span><math><mi>α</mi></math></span>-AlFeSi and <span><math><mi>β</mi></math></span>-AlFeSi IMCs, and show direct insights into their formation sequence and kinetics. Contrary to widely held assumptions based on low Fe-containing (<span><math><mo>&lt;</mo></math></span>0.6 wt%) primary alloys, we show that in recycled alloys containing higher Fe concentrations, increased cooling rate significantly promotes the formation of the more anisotropic <span><math><mi>β</mi></math></span>-AlFeSi (over the more compact <span><math><mi>α</mi></math></span>-AlFeSi), which however can be fully suppressed at slow cooling. We propose how a solute-suppression mechanism kinetically controls the <span><math><mi>α</mi></math></span>/<span><math><mi>β</mi></math></span> IMC phase evolution. Further, we reveal and quantify a faceted-to-non-faceted morphological transition of <span><math><mi>α</mi></math></span>-AlFeSi from a faceted polyhedral to non-faceted near-equiaxed dendritic morphology. This transition is governed by an interplay between solidification velocity and liquid undercooling at the local IMC/liquid interfaces. This study provides insights into how solidification conditions may be leveraged to improve microstructural control in high Fe-containing recycled alloys.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"301 ","pages":"Article 121591"},"PeriodicalIF":9.3,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145216170","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":"Microstructural features governing the effective thermal conductivity of Cu-25Cr sintered composites","authors":"Lucas Varoto ,&nbsp;Elodie Courtois ,&nbsp;Raymond Kwesi Nutor ,&nbsp;Sophie Roure ,&nbsp;Anthony Papillon ,&nbsp;Mélissa Chosson ,&nbsp;Baptiste Gault ,&nbsp;Pierre Lhuissier ,&nbsp;Jean-Jacques Blandin ,&nbsp;Guilhem Martin","doi":"10.1016/j.actamat.2025.121601","DOIUrl":"10.1016/j.actamat.2025.121601","url":null,"abstract":"<div><div>Medium voltage vacuum interrupters are high-performance current interruption devices in the contemporary energy transition and electrification. The current interruption performance is directly correlated to the properties of their electrical contacts made of Cu-Cr alloys. Therefore, enhancing their performance to respond to the continuously increasing demand for higher current, higher power, and high voltage applications inherently requires the optimization of the microstructure of the Cu-Cr alloys to increase their electrical and thermal conductivity. Herein, we unveil the microstructural features governing the effective thermal conductivity of Cu-25Cr sintered composites, a subject of much less scientific attention than their electrical conductivity due to the complex microstructure-thermal conduction relationships. We coupled advanced 3D characterization techniques, namely X-ray computed tomography and atom probe tomography, with experimental and full-field numerical investigation of the effective thermal conductivity for three Cu-25Cr sintered composites having different final relative density (94, 96, and 98%). We demonstrate the synergistic effect of solid solution, interfacial thermal resistance, phase distribution on the effective thermal conductivity. Interfacial pores hinder the thermal conduction across phases. The effective thermal conductivity also decreases due to elements in solid-solution that diffused in the Cu matrix during sintering, along with interfacial thermal resistance across Cu/Cr phases. Using a full-field numerical approach, we unravel a microstructure heterogeneity-induced heat flux anisotropy contributing to the anisotropy in effective thermal conductivity.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"301 ","pages":"Article 121601"},"PeriodicalIF":9.3,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145203335","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":"Deformation mechanisms of Al alloys containing shearable/non-shearable L12 precipitates: A comparative study under varied slip system activations","authors":"Jing Dai ,&nbsp;Han Chen ,&nbsp;Yuchi Cui ,&nbsp;Chengyi Dan ,&nbsp;Shuwei Zong ,&nbsp;Chen Yang ,&nbsp;Hengfu Li ,&nbsp;Xiang Chen ,&nbsp;Hongru Zhong ,&nbsp;Haowei Wang ,&nbsp;Zhe Chen","doi":"10.1016/j.actamat.2025.121607","DOIUrl":"10.1016/j.actamat.2025.121607","url":null,"abstract":"<div><div>Although the shearing and bypassing mechanisms have been extensively studied in precipitation-hardened alloys, the effects of shearable and non-shearable precipitates under multiple slip system activation remain not fully understood. This study explores the influence of shearable and non-shearable Al₃(Sc, Zr) precipitates on the deformation behavior of Al–Mg–Sc–Zr alloy through micropillar compression tests under three distinct crystallographic orientations: single-slip, coplanar double-slip and non-coplanar double-slip. In single-slip micropillars, shearable precipitates allow dislocations to cut through, resulting in low dislocation storage. In contrast, non-shearable precipitates cause dislocations to bypass via Orowan looping, promoting secondary slip activation and increasing dislocation storage and strain hardening. In coplanar double-slip micropillars, the effect of precipitate type is diminished. Coplanar dislocation reactions forming quadrilateral dislocation structures that suppress secondary slip activation with non-shearable precipitates and increase dislocation storage in those with shearable precipitates, resulting in similar hardening behavior. However, in non-coplanar double-slip micropillars, the effect of precipitate type is drastically pronounced. In micropillars with non-shearable precipitates, complex dislocation interactions (between primary/secondary slip systems and non-coplanar reactive dislocations) lead to cellular dislocation structures and enhanced strain hardening. This work highlights the critical roles of precipitates and slip system activation in governing the underlying deformation mechanisms.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"301 ","pages":"Article 121607"},"PeriodicalIF":9.3,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145203333","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":"In-situ TEM observation of the seed-free growth of five-fold twinned Au decahedra","authors":"Anqi Zheng ,&nbsp;Rui Pan ,&nbsp;Yuheng Huang ,&nbsp;Mao Ye ,&nbsp;Kuibo Yin ,&nbsp;Litao Sun","doi":"10.1016/j.actamat.2025.121609","DOIUrl":"10.1016/j.actamat.2025.121609","url":null,"abstract":"<div><div>Five-fold twinned decahedral nanoparticles exhibit exceptional properties due to their unique symmetry, yet seed-free formation mechanisms remain elusive despite extensive research relying on pre-existing twinned seeds or tetrahedral building blocks. Here, we report the seed-free evolution of polycrystalline Au nanoparticles into five-fold twinned decahedra using in-situ high-resolution transmission electron microscopy, revealing a new multi-stage growth mechanism involving reversible phase transitions. The pathway proceeds through: curvature-driven atomic diffusion initiating particle necking; subsequent localized atomic rearrangements yield coherent twin boundaries; and reversible <em>fcc</em>–2H-polytype <em>hcp</em>–<em>fcc</em> phase transitions within twin domains enable lattice reconstruction through coordinated atomic sliding. Transient stacking faults act as pivotal structural mediators that facilitate atomic migration, significantly reducing energy barriers and stabilizing the emergent twinned lattice. These findings advance the mechanistic understanding of seed-free formation of five-fold twinned Au nanostructures and facilitate the rational design of multiply nanoparticles.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"301 ","pages":"Article 121609"},"PeriodicalIF":9.3,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145203334","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}