Acta Materialia最新文献_第9页

Atomic-scale insights into the exceptional pinning effect of the K bubbles on W grain boundary 原子尺度上对K气泡在W晶界上的特殊钉住效应的洞察

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2025-12-18 DOI: 10.1016/j.actamat.2025.121845

Ming Chen , Linfu Zhang , Kang Liu , Qiang Zhu , Jie Xu , Bin Guo , Debin Shan , Hushan Li , Guohua Fan , Tao Yang , Yinghao Zhou , Peng Zhang

The application of tungsten (W) as plasma-facing materials (PFMs) in nuclear fusion reactors is limited by its low recrystallization temperature (RCT) and significant grain growth at elevated temperatures. Potassium (K)-doped W exhibits remarkably enhanced thermal stability due to nanoscale K bubbles, yet the atomic-scale pinning mechanism remains unclear. In this study, a high-precision neuroevolution potential (NEP) for the W-K system was developed using machine learning, and molecular dynamics (MD) simulations were performed to elucidate the unique pinning effect of the K bubbles on grain boundary (GB) migration. Our findings reveal that K bubbles exhibit distinct pinning characteristics compared to solid second-phase particles. Through quantification of GB migration velocity changes before and after the K bubble incorporation, the average pinning forces exerted by bubbles of different sizes were calculated, all of which were found to significantly exceed the maximum pinning forces predicted by classical Zener theory for solid particles of equivalent dimensions. The exceptional pinning capability is attributed to the high deformability of K bubbles, which exhibit substantial elongation and surface wrinkling during GB interactions, consequently expanding the contact area and amplifying pinning effectiveness. The findings lead to the proposition of a "deformation-enhanced pinning" mechanism that fundamentally accounts for the remarkable grain growth suppression achieved by trace K doping (<100 ppm). This work provides crucial theoretical guidance for designing advanced PFMs with superior thermal stability, paving the way for developing next-generation fusion materials.

钨(W)作为等离子体表面材料（PFMs）在核聚变反应堆中的应用受到其再结晶温度（RCT）低和高温下晶粒生长明显的限制。由于纳米级的K气泡，钾(K)掺杂W表现出显著增强的热稳定性，但原子尺度的钉钉机制尚不清楚。在这项研究中，利用机器学习开发了W-K系统的高精度神经进化电位（NEP），并进行了分子动力学（MD）模拟来阐明K气泡对晶界（GB）迁移的独特钉住效应。我们的研究结果表明，与固体第二相颗粒相比，K气泡具有明显的钉住特性。通过量化K泡掺入前后GB迁移速度的变化，计算了不同尺寸气泡所施加的平均钉住力，均明显超过经典齐纳理论对等尺寸固体颗粒所预测的最大钉住力。优异的钉钉能力归因于K泡的高变形能力，在GB相互作用过程中表现出大量的延伸和表面起皱，从而扩大了接触面积，增强了钉钉效果。这些发现导致了“变形增强钉钉”机制的提出，该机制从根本上解释了微量K掺杂（<100 ppm）对晶粒生长的显著抑制。这项工作为设计具有优异热稳定性的先进pfm提供了重要的理论指导，为开发下一代聚变材料铺平了道路。

{"title":"Atomic-scale insights into the exceptional pinning effect of the K bubbles on W grain boundary","authors":"Ming Chen , Linfu Zhang , Kang Liu , Qiang Zhu , Jie Xu , Bin Guo , Debin Shan , Hushan Li , Guohua Fan , Tao Yang , Yinghao Zhou , Peng Zhang","doi":"10.1016/j.actamat.2025.121845","DOIUrl":"10.1016/j.actamat.2025.121845","url":null,"abstract":"<div><div>The application of tungsten (W) as plasma-facing materials (PFMs) in nuclear fusion reactors is limited by its low recrystallization temperature (RCT) and significant grain growth at elevated temperatures. Potassium (K)-doped W exhibits remarkably enhanced thermal stability due to nanoscale K bubbles, yet the atomic-scale pinning mechanism remains unclear. In this study, a high-precision neuroevolution potential (NEP) for the W-K system was developed using machine learning, and molecular dynamics (MD) simulations were performed to elucidate the unique pinning effect of the K bubbles on grain boundary (GB) migration. Our findings reveal that K bubbles exhibit distinct pinning characteristics compared to solid second-phase particles. Through quantification of GB migration velocity changes before and after the K bubble incorporation, the average pinning forces exerted by bubbles of different sizes were calculated, all of which were found to significantly exceed the maximum pinning forces predicted by classical Zener theory for solid particles of equivalent dimensions. The exceptional pinning capability is attributed to the high deformability of K bubbles, which exhibit substantial elongation and surface wrinkling during GB interactions, consequently expanding the contact area and amplifying pinning effectiveness. The findings lead to the proposition of a \"deformation-enhanced pinning\" mechanism that fundamentally accounts for the remarkable grain growth suppression achieved by trace K doping (<100 ppm). This work provides crucial theoretical guidance for designing advanced PFMs with superior thermal stability, paving the way for developing next-generation fusion materials.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"305 ","pages":"Article 121845"},"PeriodicalIF":9.3,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145784599","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}

引用次数: 0

Achieving strength-ductility synergy in Mg-Li alloy via heterogeneous structure and shearable precipitates 通过非均相组织和可剪切析出物实现Mg-Li合金强度-延性协同

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2025-12-17 DOI: 10.1016/j.actamat.2025.121830

Yuchuan Huang, Jiawei Sun, Fangzhou Qi, Jie Wang, Yangyang Xu, Jiaxin Yu, Youjie Guo, Guohua Wu, Wencai Liu

Balancing strength and ductility remains a major challenge in lightweight Mg alloys. In this study, a novel Mg-Li-Al-Zn (LAZ432) alloy was designed and fabricated with a lamellar heterogeneous structure reinforced by semi-coherent (Mg,Li)(Al,Zn)₂ precipitates. This structure is formed through a simple and controllable thermos-mechanical process based on particle stimulated nucleation enabling a superior strength-ductility synergy. The alloy exhibits the excellent combination of ultimate tensile strength (∼346 MPa) and elongation (∼30.0 %), with a high strength-elongation product of 10.4 GPa %. The enhanced strength primarily arises from hetero-deformation induced (HDI) strengthening at coarse-fine grain interfaces, precipitation strengthening from coherent shearable precipitates, and sustained work hardening through the progressive accumulation of dislocations. Meanwhile, efficient strain partitioning across the heterogeneous regions and internal micro-strain within the shearable precipitates collectively suppress strain concentration and promote more uniform plastic deformation. Furthermore, the addition of Li reduces the lattice c/a ratio, facilitating the activation of pyramidal 〈c + a〉 slip and enhancing overall plasticity.

平衡强度和延展性仍然是轻量化镁合金面临的主要挑战。在本研究中，设计并制备了一种新型的Mg-Li-Al-Zn （LAZ432）合金，该合金具有半相干（Mg,Li）（Al,Zn）2相增强的片层非均质结构。这种结构是通过简单可控的热-机械过程形成的，基于粒子激发成核，从而实现了卓越的强度-延性协同作用。该合金具有优异的抗拉强度（~ 346MPa）和伸长率（~ 30.0%）组合，强度-伸长率高达10.4 GPa·%。强度的增强主要来自粗-细晶粒界面的异质变形诱导强化、共格可剪切析出相的析出强化以及位错累进累积的持续加工硬化。同时，非均质区域的有效应变分配和可剪切析出相内部的微应变共同抑制了应变集中，促进了更均匀的塑性变形。此外，Li的加入降低了晶格c/a比，促进了锥体<；c+ >；滑移的激活，提高了整体塑性。

{"title":"Achieving strength-ductility synergy in Mg-Li alloy via heterogeneous structure and shearable precipitates","authors":"Yuchuan Huang, Jiawei Sun, Fangzhou Qi, Jie Wang, Yangyang Xu, Jiaxin Yu, Youjie Guo, Guohua Wu, Wencai Liu","doi":"10.1016/j.actamat.2025.121830","DOIUrl":"10.1016/j.actamat.2025.121830","url":null,"abstract":"<div><div>Balancing strength and ductility remains a major challenge in lightweight Mg alloys. In this study, a novel Mg-Li-Al-Zn (LAZ432) alloy was designed and fabricated with a lamellar heterogeneous structure reinforced by semi-coherent (Mg,Li)(Al,Zn)<sub>2</sub> precipitates. This structure is formed through a simple and controllable thermos-mechanical process based on particle stimulated nucleation enabling a superior strength-ductility synergy. The alloy exhibits the excellent combination of ultimate tensile strength (∼346 MPa) and elongation (∼30.0 %), with a high strength-elongation product of 10.4 GPa %. The enhanced strength primarily arises from hetero-deformation induced (HDI) strengthening at coarse-fine grain interfaces, precipitation strengthening from coherent shearable precipitates, and sustained work hardening through the progressive accumulation of dislocations. Meanwhile, efficient strain partitioning across the heterogeneous regions and internal micro-strain within the shearable precipitates collectively suppress strain concentration and promote more uniform plastic deformation. Furthermore, the addition of Li reduces the lattice c/a ratio, facilitating the activation of pyramidal 〈<em>c</em> + <em>a〉</em> slip and enhancing overall plasticity.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"305 ","pages":"Article 121830"},"PeriodicalIF":9.3,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771373","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}

引用次数: 0

Revealing the three-dimensional morphology and formation process of Fe-contained intermetallic compounds in aluminum alloys: A combined first-principles, phase field, and FIB-SEM tomography study 揭示铝合金中含铁金属间化合物的三维形态和形成过程：结合第一性原理，相场和FIB-SEM断层扫描研究

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2025-12-17 DOI: 10.1016/j.actamat.2025.121835

Jiale Ma , Yanli Zhang , Qing Peng , Qingyan Xu , Haidong Zhao , Zhiqiang Han

The three-dimensional morphology and formation process of Fe-contained intermetallic compounds (IMCs), known to impair the mechanical properties of aluminum (Al) alloys, have long remained an unsolved mystery. This lack of fundamental understanding hindered the development of strategies for their morphological control. In this work, the formation process of Fe-contained IMCs in Al alloys was revealed for the first time through a rigorously physics-based approach, combining first-principles/phase field modeling and focused ion beam-scanning electron microscopy (FIB-SEM) tomography. The unique contributions of this research lie in three aspects: First, we performed first-principles calculations to determine the interfacial energies of π-AlFeMgSi, α-AlFeMnSi, and β-AlFeSi phases along multiple crystallographic orientations, and provided a quantitative description for their anisotropic interfacial energies, representing the first report of such fundamental data. Subsequently, the anisotropic interfacial energies were parametrized into phase field models to examine the morphology evolution of Fe-contained IMCs. Two distinct growth modes, free growth in melt and concurrent growth with Al phases, were proposed innovatively, both of which are proved by experiments. Moreover, instead of the widely used X-ray imaging methods, which struggle to differentiate Fe-contained IMCs from other IMCs because of comparable X-ray absorption, FIB-SEM tomography was applied to specifically characterize the three-dimensional morphology of Chinese-script α-AlFeMnSi phases. A novel interpretation for the formation mechanism of this intricate morphology was proposed, which is further elucidated by phase field modeling. This study offered unprecedented insights into the morphology and formation process of Fe-contained IMCs, exploring a way for the rational design of morphology control strategies.

含铁金属间化合物（IMCs）的三维形态和形成过程，已知会损害铝（Al）合金的机械性能，长期以来一直是一个未解之谜。缺乏基本的认识阻碍了其形态控制策略的发展。在这项工作中，首次通过严格的基于物理的方法，结合第一性原理/相场建模和聚焦离子束扫描电子显微镜（FIB-SEM）断层扫描，揭示了Al合金中含铁IMCs的形成过程。本研究的独特贡献在于：第一，通过第一性原理计算确定了π-AlFeMgSi、α-AlFeMnSi和β-AlFeSi相沿多晶向的界面能，并对其各向异性界面能进行了定量描述，首次报道了这类基础数据；随后，将各向异性界面能参数化为相场模型，考察含铁IMCs的形貌演变。创新性地提出了熔体自由生长和Al相同步生长两种不同的生长模式，并通过实验加以验证。此外，广泛使用的x射线成像方法很难区分含铁的IMCs与其他IMCs，因为它们具有相似的x射线吸收，而FIB-SEM断层扫描被用于具体表征汉字α-AlFeMnSi相的三维形态。对这种复杂形态的形成机理提出了一种新的解释，并通过相场模型进一步阐明了这一解释。本研究对含铁IMCs的形态和形成过程提供了前所未有的认识，为合理设计形态控制策略探索了一条途径。

{"title":"Revealing the three-dimensional morphology and formation process of Fe-contained intermetallic compounds in aluminum alloys: A combined first-principles, phase field, and FIB-SEM tomography study","authors":"Jiale Ma , Yanli Zhang , Qing Peng , Qingyan Xu , Haidong Zhao , Zhiqiang Han","doi":"10.1016/j.actamat.2025.121835","DOIUrl":"10.1016/j.actamat.2025.121835","url":null,"abstract":"<div><div>The three-dimensional morphology and formation process of Fe-contained intermetallic compounds (IMCs), known to impair the mechanical properties of aluminum (Al) alloys, have long remained an unsolved mystery. This lack of fundamental understanding hindered the development of strategies for their morphological control. In this work, the formation process of Fe-contained IMCs in Al alloys was revealed for the first time through a rigorously physics-based approach, combining first-principles/phase field modeling and focused ion beam-scanning electron microscopy (FIB-SEM) tomography. The unique contributions of this research lie in three aspects: First, we performed first-principles calculations to determine the interfacial energies of π-AlFeMgSi, α-AlFeMnSi, and β-AlFeSi phases along multiple crystallographic orientations, and provided a quantitative description for their anisotropic interfacial energies, representing the first report of such fundamental data. Subsequently, the anisotropic interfacial energies were parametrized into phase field models to examine the morphology evolution of Fe-contained IMCs. Two distinct growth modes, free growth in melt and concurrent growth with Al phases, were proposed innovatively, both of which are proved by experiments. Moreover, instead of the widely used X-ray imaging methods, which struggle to differentiate Fe-contained IMCs from other IMCs because of comparable X-ray absorption, FIB-SEM tomography was applied to specifically characterize the three-dimensional morphology of Chinese-script α-AlFeMnSi phases. A novel interpretation for the formation mechanism of this intricate morphology was proposed, which is further elucidated by phase field modeling. This study offered unprecedented insights into the morphology and formation process of Fe-contained IMCs, exploring a way for the rational design of morphology control strategies.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"305 ","pages":"Article 121835"},"PeriodicalIF":9.3,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771739","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}

引用次数: 0

Hidden complexity in D2O Ice VII D2O冰VII中隐藏的复杂性

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2025-12-17 DOI: 10.1016/j.actamat.2025.121839

Wojciech A. Sławiński , Grzegorz Łach , Roman Gajda , Michał Chodkiewicz , Piotr Rejnhardt , Mihails Arhangelskis , Christopher L. Ridley , Craig L. Bull , Krzysztof Woźniak

Ice VII is thought to play a role in the water-rich interiors of Jupiter's moon Europa, Saturn's moon Enceladus and other planetary bodies. Althow its average cubic structure appears simple, the local structure reveals hidden complexity: individual positions of water molecules forming a complex network via hydrogen bonds. Through coupling Pair Distribution Function and Reverse Monte Carlo modelling to high pressure neutron scattering data, we have quantified the atomic and molecular structures of disordered ice VII. The decomposition of the average structure of ice VII into the individual positions of water molecules within the crystal lattice reveals that the D₂O molecules are displaced along the direction of the polarization vector of each molecule. Incorporating this displacement yields a structural model that more accurately reproducs the D–O distances and D–O–D angles determined for other ordered ice structures. Our results are also supported by DFT calculations confirming that deviations of water molecules from their average crystallographic positions energetically stabilize the structure of ice VII. Our results open new perspectives for structural studies of different forms of ice, their phase transitions treating them as vast clusters of molecules with an average periodic structure but symmetry-free local arrangements.

人们认为，“冰七号”在木星的卫星木卫二、土星的卫星土卫二和其他行星体富含水的内部发挥了作用。从冰七的平均立方结构来看，看似简单，但局部结构却隐藏着复杂性，即水分子的单个位置通过氢键形成复杂的网络。通过对高压中子散射数据的耦合对分布函数和反向蒙特卡罗建模，对无序冰VII的原子和分子结构进行了量化。将冰七的平均结构分解为晶格内水分子的个别位置，表明D2O分子沿着每个分子的偏振矢量方向移位。通过应用这种位移，结构模型更准确地匹配从其他有序冰结构确定的D-O距离和D-O - d角度。我们的结果也得到了DFT计算的支持，证实了水分子偏离其平均晶体位置在能量上稳定了冰VII的结构。我们的研究为不同形式冰的结构研究开辟了新的视角，它们的相变将它们视为具有平均周期结构但不对称局部排列的巨大分子簇。

{"title":"Hidden complexity in D2O Ice VII","authors":"Wojciech A. Sławiński , Grzegorz Łach , Roman Gajda , Michał Chodkiewicz , Piotr Rejnhardt , Mihails Arhangelskis , Christopher L. Ridley , Craig L. Bull , Krzysztof Woźniak","doi":"10.1016/j.actamat.2025.121839","DOIUrl":"10.1016/j.actamat.2025.121839","url":null,"abstract":"<div><div>Ice VII is thought to play a role in the water-rich interiors of Jupiter's moon Europa, Saturn's moon Enceladus and other planetary bodies. Althow its average cubic structure appears simple, the local structure reveals hidden complexity: individual positions of water molecules forming a complex network via hydrogen bonds. Through coupling Pair Distribution Function and Reverse Monte Carlo modelling to high pressure neutron scattering data, we have quantified the atomic and molecular structures of disordered ice VII. The decomposition of the average structure of ice VII into the individual positions of water molecules within the crystal lattice reveals that the D<sub>2</sub>O molecules are displaced along the direction of the polarization vector of each molecule. Incorporating this displacement yields a structural model that more accurately reproducs the D–O distances and D–O–D angles determined for other ordered ice structures. Our results are also supported by DFT calculations confirming that deviations of water molecules from their average crystallographic positions energetically stabilize the structure of ice VII. Our results open new perspectives for structural studies of different forms of ice, their phase transitions treating them as vast clusters of molecules with an average periodic structure but symmetry-free local arrangements.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"305 ","pages":"Article 121839"},"PeriodicalIF":9.3,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771375","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}

引用次数: 0

An in-situ study on the formation mechanism of adiabatic shear band in refractory high-entropy alloys 耐火高熵合金绝热剪切带形成机理的原位研究

IF 9.4 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2025-12-17 DOI: 10.1016/j.actamat.2025.121843

Jianye He, Zezhou Li, Longkang Li, Jingchen Lin, Jun Wang, Shengxin Zhu, Fan Zhang, Lin Wang, Qinglei Zeng, Haosen Chen, Xingwang Cheng

The dynamic deformation, temperature evolution, and mechanical properties of NbTaTiV and NbTaTiVW alloys were investigated through high-speed photography, infrared temperature measurement, and the split Hopkinson pressure bar. The findings reveal that the adiabatic shear band initiated in the NbTaTiV and NbTaTiVW alloys when the temperature reaches approximately 160 ℃ and 115 ℃, respectively. It is evident that dependence exclusively on the thermal softening effect is inadequate to activate adiabatic shear bands. Instead, microstructural softening emerges as the predominant factor influencing their formation. We assessed the adiabatic shear sensitivity of NbTaTiV and NbTaTiVW alloys from distinct perspectives. It is noteworthy that the defect density observed in the NbTaTiV alloy is considerably greater than that found in the NbTaTiVW alloy. The deformation structure of the NbTaTiV alloy predominantly consists of dislocations, deformation twins, and kink bands, whereas the NbTaTiVW alloy is deformed by dislocations and deformation twins. The activation of multiple slip systems within the NbTaTiV alloy contributes to the delay of adiabatic shear failure. In addition, the participate phases in the NbTaTiVW alloy facilitate an increase in local dislocation density, thereby promoting adiabatic shear band failure. As a result, the energy dissipation of the adiabatic shear bands in the NbTaTiV alloy spans from 20.4 to 100.6 kJ/m², while the energy dissipation for the NbTaTiVW alloy is from 10.1 to 35.6 kJ/m². Our results and analyses contribute to formation mechanisms of shear band in refractory high-entropy alloys subjected to high strain rates.

采用高速摄影、红外测温和分离式霍普金森压杆研究了NbTaTiV和NbTaTiVW合金的动态变形、温度演变和力学性能。结果表明：当温度分别达到160℃和115℃左右时，NbTaTiV和NbTaTiVW合金中产生绝热剪切带；显然，仅仅依靠热软化效应是不足以激活绝热剪切带的。相反，微观结构软化成为影响其形成的主要因素。我们从不同的角度评估了NbTaTiV和NbTaTiVW合金的绝热剪切敏感性。值得注意的是，在NbTaTiV合金中观察到的缺陷密度明显大于NbTaTiVW合金。NbTaTiV合金的变形组织主要是位错、变形孪晶和扭结带，而NbTaTiVW合金的变形组织主要是位错和变形孪晶。NbTaTiV合金内部多滑移系统的激活有助于延缓绝热剪切破坏。此外，NbTaTiVW合金中的参与相促进了局部位错密度的增加，从而促进了绝热剪切带的破坏。结果表明，NbTaTiV合金的绝热剪切带能量耗散范围为20.4 ~ 100.6 kJ/m²，NbTaTiVW合金的绝热剪切带能量耗散范围为10.1 ~ 35.6 kJ/m²。我们的结果和分析有助于高应变率下难熔高熵合金剪切带的形成机制。

{"title":"An in-situ study on the formation mechanism of adiabatic shear band in refractory high-entropy alloys","authors":"Jianye He, Zezhou Li, Longkang Li, Jingchen Lin, Jun Wang, Shengxin Zhu, Fan Zhang, Lin Wang, Qinglei Zeng, Haosen Chen, Xingwang Cheng","doi":"10.1016/j.actamat.2025.121843","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121843","url":null,"abstract":"The dynamic deformation, temperature evolution, and mechanical properties of NbTaTiV and NbTaTiVW alloys were investigated through high-speed photography, infrared temperature measurement, and the split Hopkinson pressure bar. The findings reveal that the adiabatic shear band initiated in the NbTaTiV and NbTaTiVW alloys when the temperature reaches approximately 160 ℃ and 115 ℃, respectively. It is evident that dependence exclusively on the thermal softening effect is inadequate to activate adiabatic shear bands. Instead, microstructural softening emerges as the predominant factor influencing their formation. We assessed the adiabatic shear sensitivity of NbTaTiV and NbTaTiVW alloys from distinct perspectives. It is noteworthy that the defect density observed in the NbTaTiV alloy is considerably greater than that found in the NbTaTiVW alloy. The deformation structure of the NbTaTiV alloy predominantly consists of dislocations, deformation twins, and kink bands, whereas the NbTaTiVW alloy is deformed by dislocations and deformation twins. The activation of multiple slip systems within the NbTaTiV alloy contributes to the delay of adiabatic shear failure. In addition, the participate phases in the NbTaTiVW alloy facilitate an increase in local dislocation density, thereby promoting adiabatic shear band failure. As a result, the energy dissipation of the adiabatic shear bands in the NbTaTiV alloy spans from 20.4 to 100.6 kJ/m², while the energy dissipation for the NbTaTiVW alloy is from 10.1 to 35.6 kJ/m². Our results and analyses contribute to formation mechanisms of shear band in refractory high-entropy alloys subjected to high strain rates.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"11 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771374","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}

引用次数: 0

Fracture mode and toughening mechanism induced by microstructure in binderless WC cemented carbides: A phase-field simulation integrating energy dissipation analysis 无粘结WC硬质合金微观组织诱导的断裂模式及增韧机制：相场模拟与能量耗散分析

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2025-12-17 DOI: 10.1016/j.actamat.2025.121834

Yiqi Guan , Zhixuan Zhang , Meifang Tang , Meiling He , Xiangyu Yan , Jianzhan Long , Qi Huang , Weibin Zhang , Yong Du , Alexander Hartmaier

The intrinsic trade-off between hardness and fracture toughness in carbide ceramics poses a severe challenge to their broader applications in advanced manufacturing. While grain refinement is known to enhance both properties, the underlying mechanisms through which microstructural factors (including grain size, grain orientation, and grain boundaries) govern crack propagation remain insufficiently understood. In this study, the fracture energy dissipation-based evaluation model within the phase-field framework was established to visualize fracture resistance in binderless WC cemented carbides. By integrating this model with experimental characterization, the influence of grain-scale microstructural factors on crack propagation was systematically investigated. The results reveal that the orientation-dependent fracture resistance of WC grains, grain boundary inclination, and especially grain size strongly influence the fracture mode and energy dissipation. Notably, grain refinement induces the increasement of transgranular fracture proportion, significantly increasing fracture energy dissipation. The binderless WC cemented carbide with finer grains (0.96 ± 0.01 μm) achieves a balanced combination of high fracture toughness (6.23 ± 0.16

MPa \cdot m^{1 / 2}

) and hardness (2231.19 ± 37.96

HV

). Both experimental and simulation results confirm that WC grain refinement is an effective strategy for improving fracture resistance, thereby validating the effectiveness of the fracture energy dissipation assessment model. The presently developed methodology provides critical insights into microstructure–crack interactions and opens new avenues for the microstructural design of high-toughness carbide ceramics.

碳化物陶瓷的硬度和断裂韧性之间的内在平衡对其在先进制造中的广泛应用提出了严峻的挑战。虽然已知晶粒细化可以增强这两种性能，但微观结构因素（包括晶粒尺寸、晶粒取向和晶界）控制裂纹扩展的潜在机制仍未得到充分了解。在本研究中，建立了相场框架下基于断裂能量耗散的评估模型，以可视化无粘结剂WC硬质合金的断裂抗力。将该模型与实验表征相结合，系统研究了晶粒级微观组织因素对裂纹扩展的影响。结果表明，WC晶粒的抗断裂能力、晶界倾角，尤其是晶粒尺寸对其断裂模式和能量耗散有较大影响。晶粒细化导致穿晶断裂比例增加，断裂能量耗散显著增加。晶粒细（0.96±0.01 μm）的无粘结WC硬质合金具有较高的断裂韧性（6.23±0.16 MPa·m1/2MPa·m1/2）和硬度（2231.19±37.96 HVHV）。实验和仿真结果均证实WC晶粒细化是提高抗断裂能力的有效策略，从而验证了断裂能量耗散评估模型的有效性。目前开发的方法为微结构-裂纹相互作用提供了重要的见解，并为高韧性碳化物陶瓷的微结构设计开辟了新的途径。

{"title":"Fracture mode and toughening mechanism induced by microstructure in binderless WC cemented carbides: A phase-field simulation integrating energy dissipation analysis","authors":"Yiqi Guan , Zhixuan Zhang , Meifang Tang , Meiling He , Xiangyu Yan , Jianzhan Long , Qi Huang , Weibin Zhang , Yong Du , Alexander Hartmaier","doi":"10.1016/j.actamat.2025.121834","DOIUrl":"10.1016/j.actamat.2025.121834","url":null,"abstract":"<div><div>The intrinsic trade-off between hardness and fracture toughness in carbide ceramics poses a severe challenge to their broader applications in advanced manufacturing. While grain refinement is known to enhance both properties, the underlying mechanisms through which microstructural factors (including grain size, grain orientation, and grain boundaries) govern crack propagation remain insufficiently understood. In this study, the fracture energy dissipation-based evaluation model within the phase-field framework was established to visualize fracture resistance in binderless WC cemented carbides. By integrating this model with experimental characterization, the influence of grain-scale microstructural factors on crack propagation was systematically investigated. The results reveal that the orientation-dependent fracture resistance of WC grains, grain boundary inclination, and especially grain size strongly influence the fracture mode and energy dissipation. Notably, grain refinement induces the increasement of transgranular fracture proportion, significantly increasing fracture energy dissipation. The binderless WC cemented carbide with finer grains (0.96 ± 0.01 μm) achieves a balanced combination of high fracture toughness (6.23 ± 0.16 <span><math><mrow><mtext>MPa</mtext><mo>·</mo><msup><mrow><mrow><mi>m</mi></mrow></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></mrow></math></span>) and hardness (2231.19 ± 37.96 <span><math><mtext>HV</mtext></math></span>). Both experimental and simulation results confirm that WC grain refinement is an effective strategy for improving fracture resistance, thereby validating the effectiveness of the fracture energy dissipation assessment model. The presently developed methodology provides critical insights into microstructure–crack interactions and opens new avenues for the microstructural design of high-toughness carbide ceramics.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"305 ","pages":"Article 121834"},"PeriodicalIF":9.3,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771371","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}

引用次数: 0

Preserving nanograined structure of ferritic steel during high-temperature sintering 铁素体钢在高温烧结过程中保持纳米晶粒结构

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2025-12-16 DOI: 10.1016/j.actamat.2025.121837

X.C. Cai , B.B. He , M.X. Huang

Ferritic steels with a nanograined structure are highly desirable for extreme applications in advanced nuclear reactors. Although nanograins can be readily generated through mechanical alloying, pronounced grain coarsening frequently occurs during the subsequent high-temperature sintering process, making it challenging to maintain the nanograined structure. The present work demonstrates that minor Zr alloying (0.8 wt.%, nominal) can effectively preserve the nanograined structure in typical ferritic oxide-dispersion-strengthened steels during high-temperature sintering via promoting homogeneous nanoprecipitation. To explore the role of Zr in influencing the precipitation of oxide nanoparticles (NPs), a series of multi-scale microstructural characterizations are performed. Contrary to the conventional view that Zr greatly accelerates the initial nucleation rate of NPs, this study reveals that Zr microalloying primarily operates by consuming excess oxygen during mechanical alloying, promptly eliminating the formation of competing oxides that are typically observed in steels without Zr. Consequently, Zr addition promotes the homogeneous precipitation of high-density Zr-Ti-O-rich NPs, which generate a strong dynamic pinning force that stabilizes the nanograins during high-temperature sintering, resulting in a nanograined ferritic steel with an average grain size of approximately 77 nm. This study highlights the often-overlooked issue of oxygen contamination control - an important consideration in the field of nanocrystalline metals and alloys fabricated by powder metallurgy and offers a cost-effective approach for designing high-performance nanostructured steels by precisely controlling the oxide NPs, which is supported by a deep understanding of the precipitation behaviors and their interactions with the nanostructure evolution.

具有纳米晶粒结构的铁素体钢在先进核反应堆的极端应用中是非常理想的。虽然通过机械合金化可以很容易地生成纳米晶粒，但在随后的高温烧结过程中，晶粒往往会出现明显的粗化，这给保持纳米晶粒结构带来了挑战。本研究表明，在高温烧结过程中，少量Zr合金（0.8 wt.%，标称）通过促进均匀的纳米沉淀，可以有效地保持典型铁素体氧化物分散强化钢的纳米晶粒结构。为了探索Zr对氧化纳米颗粒（NPs）析出的影响，进行了一系列多尺度的微观结构表征。与传统观点相反，Zr大大加快了NPs的初始形核速率，该研究表明，Zr微合金化主要是通过在机械合金化过程中消耗多余的氧气来实现的，迅速消除了在不含Zr的钢中通常观察到的竞争性氧化物的形成。因此，Zr的加入促进了高密度的富Zr- ti - o NPs的均匀析出，产生了强大的动态钉住力，在高温烧结过程中稳定了纳米晶粒，得到了平均晶粒尺寸约为77 nm的纳米铁素体钢。本研究强调了氧污染控制这一经常被忽视的问题——这是粉末冶金纳米晶金属和合金制造领域的一个重要考虑因素，并为通过精确控制氧化物NPs来设计高性能纳米结构钢提供了一种经济有效的方法，这得到了对沉淀行为及其与纳米结构演变相互作用的深入理解的支持。

{"title":"Preserving nanograined structure of ferritic steel during high-temperature sintering","authors":"X.C. Cai , B.B. He , M.X. Huang","doi":"10.1016/j.actamat.2025.121837","DOIUrl":"10.1016/j.actamat.2025.121837","url":null,"abstract":"<div><div>Ferritic steels with a nanograined structure are highly desirable for extreme applications in advanced nuclear reactors. Although nanograins can be readily generated through mechanical alloying, pronounced grain coarsening frequently occurs during the subsequent high-temperature sintering process, making it challenging to maintain the nanograined structure. The present work demonstrates that minor Zr alloying (0.8 wt.%, nominal) can effectively preserve the nanograined structure in typical ferritic oxide-dispersion-strengthened steels during high-temperature sintering via promoting homogeneous nanoprecipitation. To explore the role of Zr in influencing the precipitation of oxide nanoparticles (NPs), a series of multi-scale microstructural characterizations are performed. Contrary to the conventional view that Zr greatly accelerates the initial nucleation rate of NPs, this study reveals that Zr microalloying primarily operates by consuming excess oxygen during mechanical alloying, promptly eliminating the formation of competing oxides that are typically observed in steels without Zr. Consequently, Zr addition promotes the homogeneous precipitation of high-density Zr-Ti-O-rich NPs, which generate a strong dynamic pinning force that stabilizes the nanograins during high-temperature sintering, resulting in a nanograined ferritic steel with an average grain size of approximately 77 nm. This study highlights the often-overlooked issue of oxygen contamination control - an important consideration in the field of nanocrystalline metals and alloys fabricated by powder metallurgy and offers a cost-effective approach for designing high-performance nanostructured steels by precisely controlling the oxide NPs, which is supported by a deep understanding of the precipitation behaviors and their interactions with the nanostructure evolution.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"305 ","pages":"Article 121837"},"PeriodicalIF":9.3,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145760212","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}

引用次数: 0

Linking atomistic and phase-field modeling of grain boundaries II: Incorporating atomistic potentials into free energy functional 连接晶界的原子与相场模型II：将原子势纳入自由能泛函

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2025-12-16 DOI: 10.1016/j.actamat.2025.121787

Theophilus Wallis , Reza Darvishi Kamachali

The density-based phase-field model for grain boundary (GB) thermodynamics and kinetics has offered a broad range of applications in alloy and microstructure design. Originally, this model is based on a potential energy terms that is connected to the cohesive energy of a given substance. A more rigorous approach, however, is a full consideration of an interatomic potential over the possible range of distance and therefore density. In Manuscript I of this series (Acta Materialia (2026) 121786), we developed and thoroughly analyzed the coarse-graining of atomistic GB structures. In this work (Manuscript II), we complete the coupling between atomic and mesoscale modeling of GBs by incorporating the full interatomic potentials into the density-based free energy functional. Using GB energies calculated from atomistic simulations, the coarse-graining approach and the atomistic-integrated density-based Gibbs free energy, we effectively evaluate the density gradient energy coefficient. We found that coupling the density-based model with atomistic potentials reveal physically-sound trends in the GB equilibrium properties. A universal equation was derived to describe the potential energy contribution to the GB energy and the gradient energy coefficient for BCC-Fe and -Mo GBs, similar to the universal equation for GB excess free volume presented in Manuscript I. The proposed approach provides a mesoscale density-based model rooted in atomic-scale characteristics for reliable predictions of GB properties.

基于密度的晶界热力学和动力学相场模型在合金和显微组织设计中有着广泛的应用。最初，该模型是基于与给定物质的内聚能相关的势能项。然而，更严格的方法是在可能的距离和密度范围内充分考虑原子间势。在本系列的手稿1 （Wallis and Darvishi Kamachali, 2025）中，我们发展并深入分析了原子GB结构的粗粒度。在本文中（手稿II），我们通过将完整的原子间电位纳入基于密度的自由能泛函中，完成了原子和中尺度模拟之间的耦合。利用原子模拟计算的GB能量、粗粒化方法和基于原子积分密度的吉布斯自由能，我们有效地评估了密度梯度能量系数。我们发现，将基于密度的模型与原子势耦合，揭示了GB平衡性质的物理合理趋势。导出了一个通用方程来描述BCC-Fe和-Mo GB的势能对GB能量和梯度能量系数的贡献，类似于手稿1中提出的GB过量自由体积的通用方程。该方法提供了一个基于原子尺度特征的基于中尺度密度的模型，用于可靠地预测GB性质。

{"title":"Linking atomistic and phase-field modeling of grain boundaries II: Incorporating atomistic potentials into free energy functional","authors":"Theophilus Wallis , Reza Darvishi Kamachali","doi":"10.1016/j.actamat.2025.121787","DOIUrl":"10.1016/j.actamat.2025.121787","url":null,"abstract":"<div><div>The density-based phase-field model for grain boundary (GB) thermodynamics and kinetics has offered a broad range of applications in alloy and microstructure design. Originally, this model is based on a potential energy terms that is connected to the cohesive energy of a given substance. A more rigorous approach, however, is a full consideration of an interatomic potential over the possible range of distance and therefore density. In Manuscript I of this series (Acta Materialia (2026) 121786), we developed and thoroughly analyzed the coarse-graining of atomistic GB structures. In this work (Manuscript II), we complete the coupling between atomic and mesoscale modeling of GBs by incorporating the full interatomic potentials into the density-based free energy functional. Using GB energies calculated from atomistic simulations, the coarse-graining approach and the atomistic-integrated density-based Gibbs free energy, we effectively evaluate the density gradient energy coefficient. We found that coupling the density-based model with atomistic potentials reveal physically-sound trends in the GB equilibrium properties. A universal equation was derived to describe the potential energy contribution to the GB energy and the gradient energy coefficient for BCC-Fe and -Mo GBs, similar to the universal equation for GB excess free volume presented in Manuscript I. The proposed approach provides a mesoscale density-based model rooted in atomic-scale characteristics for reliable predictions of GB properties.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"305 ","pages":"Article 121787"},"PeriodicalIF":9.3,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145760209","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}

引用次数: 0

Role of planar defects interactions within γ channels on creep resistance enhancement in a novel Co-Ni based superalloy γ通道内平面缺陷相互作用对新型Co-Ni基高温合金抗蠕变增强的作用

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2025-12-16 DOI: 10.1016/j.actamat.2025.121833

Yuheng Zhang , Yi Zhang , Yihuan Cao , Song Lu , Shuaicheng Zhu , Jiarui Zhu , Huadong Fu , Jianxin Xie

In this study, extensive formation of multi-type planar fault configurations and their intersections were found and examined at atomic resolution in a novel Co-Ni based wrought superalloy with exceptional creep resistance under 750 °C/620 MPa. In the initial creep strain, γ/γ′ interfacial shear arises from stacking fault (SF) propagation with characteristic widths of 5–10 nm. The steady-state creep regime reveals a coordinated deformation mechanism involving both γ′-penetrating microtwins and spatially confined V-shaped SFs within γ-channels. The SF interactions in the γ-channels not only nucleate stair-rod dislocations but also induce localized γ → HCP phase transformations. Concurrently, the sequential SF formation across adjacent {111} planes facilitates Burgers vector compensation through three leading partial dislocations, enabling formation of macroscopically zero-strain twins. Meanwhile, enhanced Co/Cr segregation along defect interfaces accelerates SF propagation while promoting cross-slip of leading partial dislocations, collectively enabling the development of high-density V-shaped fault architectures. Furthermore, the preferential segregation of W at SF-MT interfaces synergistically inhibits SF/MT propagation, while stabilizing the defect configuration, thereby improving the alloy’s creep resistance. The discovered deformation modalities enable mechanistic optimization of Co-Ni based superalloys through crystallographic defect engineering, establishing theoretical frameworks for microstructure-informed creep-resistant alloy design.

在这项研究中，在750°C/620 MPa下，在一种新型的Co-Ni基变形高温合金中发现了广泛形成的多类型平面断层结构及其交叉点，并在原子分辨率上进行了检测。在初始蠕变应变中，γ/γ′界面剪切由层错（SF）扩展产生，特征宽度为5 ~ 10 nm。稳态蠕变机制揭示了γ′穿透微孪晶和γ′通道内空间受限v型SFs的协调变形机制。γ-通道中的SF相互作用不仅能形成阶梯位错，还能诱导局部γ→HCP相变。同时，相邻{111}面的连续SF形成通过三个领先的部分位错促进了Burgers向量补偿，从而形成宏观上的零应变孪晶。同时，沿缺陷界面的Co/Cr偏析增强加速了SF的传播，同时促进了主要部分位错的交叉滑移，共同促进了高密度v形断层结构的发展。此外，W在SF-MT界面上的优先偏析协同抑制了SF/MT的扩展，同时稳定了缺陷形态，从而提高了合金的抗蠕变性能。所发现的变形模式通过晶体缺陷工程实现了Co-Ni基高温合金的机制优化，为微结构抗蠕变合金设计建立了理论框架。

{"title":"Role of planar defects interactions within γ channels on creep resistance enhancement in a novel Co-Ni based superalloy","authors":"Yuheng Zhang , Yi Zhang , Yihuan Cao , Song Lu , Shuaicheng Zhu , Jiarui Zhu , Huadong Fu , Jianxin Xie","doi":"10.1016/j.actamat.2025.121833","DOIUrl":"10.1016/j.actamat.2025.121833","url":null,"abstract":"<div><div>In this study, extensive formation of multi-type planar fault configurations and their intersections were found and examined at atomic resolution in a novel Co-Ni based wrought superalloy with exceptional creep resistance under 750 °C/620 MPa. In the initial creep strain, γ/γ′ interfacial shear arises from stacking fault (SF) propagation with characteristic widths of 5–10 nm. The steady-state creep regime reveals a coordinated deformation mechanism involving both γ′-penetrating microtwins and spatially confined V-shaped SFs within γ-channels. The SF interactions in the γ-channels not only nucleate stair-rod dislocations but also induce localized γ → HCP phase transformations. Concurrently, the sequential SF formation across adjacent {111} planes facilitates Burgers vector compensation through three leading partial dislocations, enabling formation of macroscopically zero-strain twins. Meanwhile, enhanced Co/Cr segregation along defect interfaces accelerates SF propagation while promoting cross-slip of leading partial dislocations, collectively enabling the development of high-density V-shaped fault architectures. Furthermore, the preferential segregation of W at SF-MT interfaces synergistically inhibits SF/MT propagation, while stabilizing the defect configuration, thereby improving the alloy’s creep resistance. The discovered deformation modalities enable mechanistic optimization of Co-Ni based superalloys through crystallographic defect engineering, establishing theoretical frameworks for microstructure-informed creep-resistant alloy design.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"305 ","pages":"Article 121833"},"PeriodicalIF":9.3,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145760210","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}

引用次数: 0

Insights into the complexities of diffusion-induced grain boundary migration in Fe-Cr-Ni ternary alloys Fe-Cr-Ni三元合金扩散诱导晶界迁移的复杂性

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2025-12-16 DOI: 10.1016/j.actamat.2025.121836

Kai Chen , Yuhao Zhou , Zhao Shen , Lefu Zhang , Fabio Scenini , Xiaoqin Zeng , Sergio Lozano-Perez

The paper investigates the diffusion-induced grain boundary migration (DIGM) in six Fe-Cr-Ni ternary alloys exposed to steam at 480 °C. DIGM occurs due to the outward diffusion of Fe and Cr, essential for surface oxide formation, resulting in DIGM regions depleted in Fe and Cr and enriched in Ni. A significant finding is the tendency for preferential intergranular oxidation (PIO) to occur along these migrated grain boundaries, attributed to their enhanced element diffusivity. The extents of DIGM, PIO, and surface oxide thickness exhibited notable variations across the alloys with varying Ni contents, ranging from 11 wt.% to 75 wt.%. Further theoretical analysis and diffusion-barrier modeling were introduced to clarify the mechanistic role of Fe/Ni. The results reveal that Ni content modulates the competing diffusion behaviors of Fe, Cr, and Ni along grain boundaries, leading to a compositional transition from Fe-dominated to Ni-dominated diffusion regimes. The increasing Ni concentration reduces surface oxide thickness, thereby diminishing local diffusion and influencing the extent of both PIO and DIGM. However, due to the strong coupling among DIGM, PIO, and surface oxidation, their evolution with Ni content exhibits a complex, non-monotonic trend that is difficult to quantify precisely. This complexity arises from the interplay between oxidation-driven chemical potential gradients and composition-dependent grain boundary diffusivity. Generally, DIGM promotes PIO unless the outward and inward diffusivity of elements is significantly affected by surface oxides. However, in high corrosion-resistant alloys, DIGM inhibits the occurrence of PIO by facilitating the formation of an external protective chromia layer through enhanced Cr diffusion outwards.

本文研究了6种Fe-Cr-Ni三元合金在480℃蒸汽下的扩散诱导晶界迁移（DIGM）。DIGM的发生是由于Fe和Cr的向外扩散，这是表面氧化物形成所必需的，导致DIGM区域Fe和Cr耗尽，Ni富集。一个重要的发现是，优先晶间氧化（PIO）倾向于沿着这些迁移的晶界发生，这归因于它们增强的元素扩散率。随着Ni含量的变化，DIGM、PIO和表面氧化物厚度的范围在11wt .%到75wt .%之间变化显著。进一步的理论分析和扩散势垒模型进一步阐明了Fe/Ni的机理作用。结果表明，Ni含量调节了Fe、Cr和Ni沿晶界的竞争扩散行为，导致了合金成分从Fe主导向Ni主导的扩散转变。随着Ni浓度的增加，表面氧化物厚度减小，局部扩散减弱，影响了PIO和DIGM的程度。然而，由于DIGM， PIO和表面氧化之间的强耦合，它们随Ni含量的演变呈现出复杂的非单调趋势，难以精确量化。这种复杂性源于氧化驱动的化学势梯度和成分依赖的晶界扩散率之间的相互作用。一般来说，DIGM促进PIO，除非元素的向外和向内扩散率受到表面氧化物的显著影响。然而，在高耐蚀性合金中，DIGM通过增强Cr向外扩散，促进外部保护铬层的形成，从而抑制PIO的发生。

{"title":"Insights into the complexities of diffusion-induced grain boundary migration in Fe-Cr-Ni ternary alloys","authors":"Kai Chen , Yuhao Zhou , Zhao Shen , Lefu Zhang , Fabio Scenini , Xiaoqin Zeng , Sergio Lozano-Perez","doi":"10.1016/j.actamat.2025.121836","DOIUrl":"10.1016/j.actamat.2025.121836","url":null,"abstract":"<div><div>The paper investigates the diffusion-induced grain boundary migration (DIGM) in six Fe-Cr-Ni ternary alloys exposed to steam at 480 °C. DIGM occurs due to the outward diffusion of Fe and Cr, essential for surface oxide formation, resulting in DIGM regions depleted in Fe and Cr and enriched in Ni. A significant finding is the tendency for preferential intergranular oxidation (PIO) to occur along these migrated grain boundaries, attributed to their enhanced element diffusivity. The extents of DIGM, PIO, and surface oxide thickness exhibited notable variations across the alloys with varying Ni contents, ranging from 11 wt.% to 75 wt.%. Further theoretical analysis and diffusion-barrier modeling were introduced to clarify the mechanistic role of Fe/Ni. The results reveal that Ni content modulates the competing diffusion behaviors of Fe, Cr, and Ni along grain boundaries, leading to a compositional transition from Fe-dominated to Ni-dominated diffusion regimes. The increasing Ni concentration reduces surface oxide thickness, thereby diminishing local diffusion and influencing the extent of both PIO and DIGM. However, due to the strong coupling among DIGM, PIO, and surface oxidation, their evolution with Ni content exhibits a complex, non-monotonic trend that is difficult to quantify precisely. This complexity arises from the interplay between oxidation-driven chemical potential gradients and composition-dependent grain boundary diffusivity. Generally, DIGM promotes PIO unless the outward and inward diffusivity of elements is significantly affected by surface oxides. However, in high corrosion-resistant alloys, DIGM inhibits the occurrence of PIO by facilitating the formation of an external protective chromia layer through enhanced Cr diffusion outwards.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"305 ","pages":"Article 121836"},"PeriodicalIF":9.3,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145760245","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}

引用次数: 0