International Journal of Plasticity最新文献_第5页

Effect of lattice distortion and chemical short-range order on the phase transformation behavior of high entropy alloys under high strain rates 高应变速率下晶格畸变和化学短程有序对高熵合金相变行为的影响

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-12-17 DOI: 10.1016/j.ijplas.2025.104584

Yuquan Meng , Xia Zeng , Shanshan Liu , Wanghui Li , Yunjiang Wang , Kaikai Song , Jianli Shao , Lijun Xiao , Weidong Song

Phase transformation offers a promising strategy to overcome the long-standing strength-toughness trade-off in materials by accommodating plastic deformation through strain redistribution. The FCC high entropy alloy (HEA) CoCuFeNiPd has received attention for its excellent mechanical properties due to its intense chemical short-range order (SRO)and severe lattice distortion effect (LD). In this study, the effect of SRO and LD, as well as strain rate, on the mechanical responses and phase transformation behavior of CoCuFeNiPd HEA is investigated via a combination of molecular dynamics (MD) and Monte Carlo (MC) simulations. This study demonstrates that the deformation mechanism in CoCuFeNiPd HEA transitions from dislocation slip dominance at 1 × 10⁸/s to FCC-BCCHCP phase transformation dominance at 1 × 10¹⁰/s. During the initial deformation stage, yield behavior is controlled by BCC structure nucleation. LD effects substantially reduce the nucleation barrier, promoting premature BCC formation and accelerating the yielding process. The SRO effect induces the phase transformations that predominantly occur in regions where Cu-Fe-Pd clusters aggregate, which promotes the rapid development of dislocations and maintains a high flow stress. In addition, the twinning substructures of BCC martensite by specific atom shear movements are observed under the strain rate of 10¹⁰/s, which maintains the high strength, and the subsequent HCP phase transformation provides the continuous plastic deformation. This study provides important insights into the stress-induced phase transformation mechanism under extreme strain rates.

相变提供了一个有前途的策略，以克服长期存在的强度-韧性权衡材料通过适应塑性变形通过应变再分布。FCC高熵合金（HEA） CoCuFeNiPd因其强烈的化学短程有序（SRO）和严重的晶格畸变效应（LD）而获得了优异的力学性能。在本研究中，通过分子动力学（MD）和蒙特卡罗（MC）模拟相结合，研究了SRO和LD以及应变速率对CoCuFeNiPd HEA力学响应和相变行为的影响。该研究表明，CoCuFeNiPd HEA的变形机制从1 × 10⁸/s的位错滑移优势转变为1 × 10¹⁰/s的FCC-BCCHCP相变优势。在初始变形阶段，屈服行为受BCC组织形核控制。LD效应大大降低了成核屏障，促进了BCC的过早形成，加速了屈服过程。SRO效应导致相变主要发生在Cu-Fe-Pd团簇聚集的区域，这促进了位错的快速发展并保持了较高的流变应力。此外，在1010/s应变速率下，BCC马氏体通过特定原子剪切运动形成孪晶亚结构，保持了较高的强度，随后的HCP相变提供了连续的塑性变形。该研究为极端应变速率下应力诱导相变机制的研究提供了重要见解。

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引用次数: 0

Hierarchical interfacial L12 shell formation enables stable high-temperature mechanical performance in FCC/B2 dual-phase high-entropy alloys 层次化界面L12壳层的形成使FCC/B2双相高熵合金具有稳定的高温力学性能

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-12-17 DOI: 10.1016/j.ijplas.2025.104585

Linxiang Liu , Qingfeng Wu , Zhijun Wang , Hyoung Seop Kim , Junjie Li , Lei Wang , Feng He , Jincheng Wang

L1₂-strengthened FCC/B2 dual-phase high-entropy alloys (HEAs) exhibit excellent mechanical performance across a broad temperature range, positioning them promising candidates for high-temperature structural applications. However, microstructural coarsening and associated mechanical degradation under prolonged thermal exposure remain key challenges. In this study, a representative alloy with the composition Ni_41.9Co₁₉Cr₁₀Fe₁₀Al₁₅Mo₂Ti₂B_0.1 (at. %) was subjected to long-term aging at 800 °C, revealing an unusual microstructural evolution. Beyond the expected L1₂ coarsening within the FCC phase, an interfacial L1₂ shell formed via the progressive consumption of L1₂ precipitates from both the FCC and B2 phases, ultimately encapsulating the B2 domains. This transformation produced a unique three-level hierarchical architecture: FCC matrix with intragranular L1₂ precipitates, an interfacial L1₂ shell, and a B2 core. Remarkably, despite this pronounced microstructural evolution, the alloy maintained stable strength-ductility synergy from room temperature up to 800 °C. This stability is attributed to the additional strengthening imparted by the interfacial L1₂ shell and the favorable cooperative deformation among the FCC, B2, and interfacial L1₂ phases. A quantitative strengthening model was established, revealing that the strengthening contribution of the L1₂ shell increases with increasing shell thickness and exceeds 100 MPa after 720 h of aging. These results provide valuable guidance for the design of thermally stable precipitation-strengthened dual-phase HEAs for long-term high-temperature applications.

l12增强FCC/B2双相高熵合金（HEAs）在广泛的温度范围内表现出优异的机械性能，使其成为高温结构应用的有希望的候选者。然而，长期热暴露下的显微组织粗化和相关的机械退化仍然是关键的挑战。在本研究中，具有代表性的合金成分为Ni41.9Co19Cr10Fe10Al15Mo2Ti2B0.1 (at。%)在800 °C下长期时效，显示出不同寻常的显微组织演变。除了FCC相中预期的L12粗化之外，通过FCC相和B2相中L12析出物的逐渐消耗，形成了一个界面L12壳，最终封装了B2畴。这种转变产生了独特的三层分层结构：含粒内L12沉淀的FCC基体，界面L12壳和B2核。值得注意的是，尽管有这种明显的显微组织演变，但从室温到800 °C，合金保持了稳定的强度-塑性协同作用。这种稳定性归因于界面L12壳层赋予的额外强化以及FCC、B2和界面L12相之间良好的协同变形。建立了定量强化模型，结果表明：L12壳体的强化贡献随着壳体厚度的增加而增大，时效720 h后强化贡献超过100 MPa；这些结果为长期高温应用的热稳定沉淀强化双相HEAs的设计提供了有价值的指导。

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引用次数: 0

Stress softening damage in strongly nonlinear viscoelastic soft materials: A physics-informed data-driven constitutive model with time–temperature coupling 强非线性粘弹性软材料的应力软化损伤：一个具有时间-温度耦合的物理数据驱动的本构模型

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-12-15 DOI: 10.1016/j.ijplas.2025.104582

Alireza Ostadrahimi , Amir Teimouri , Kshitiz Upadhyay , Guoqiang Li

This work introduces a constitutive modeling framework based on a physics-informed Temporal Convolutional Network (TCN) for capturing the extremely nonlinear thermoviscoelastic behavior of soft materials, including large cyclic elongations up to 200%, temperature-dependent viscoelasticity, and Mullins-type damage. In contrast to conventional Mullins or thermo-viscoelastic models—which require specifying hard-coded functional forms and calibrating numerous parameters across 8–12 experiments—the proposed framework defines a new evolution law for stress, damage, and reduced-time temperature effects through a causal temporal architecture. Time–temperature superposition is embedded directly via the Williams–Landel–Ferry (WLF) shift factor, making temperature an intrinsic driver for reduced time rather than an externally appended parameter. This allows the model to learn temperature–rate–damage coupling sequentially, without predefined analytical evolution equations. As a result, the framework requires only three experimental tests for training yet generalizes to six entirely unseen tests that span different temperatures, strain rates, cycle counts, and elongation levels. The model successfully extrapolates to regimes far outside the training domain, including temperatures not used in training, strain rates 2.5 × higher, elongations 50% greater, and significantly longer cyclic histories. Thermodynamic admissibility is promoted by softly enforcing the Clausius–Duhem inequality in the loss function, while damage evolution is constrained by physical principles. The resulting surrogate constitutes a new constitutive model expressed through physics-embedded sequence learning rather than traditional closed-form equations. The trained model is directly implementable in finite element solvers through a VUMAT subroutine, enabling predictive simulations under complex geometries and loading conditions. Its robustness to experimental uncertainty is demonstrated through accurate predictions under 20% Gaussian stress noise. Validation includes three training cases, six independent experimental tests, and a geometry-dependent deployment example involving cyclic Mullins damage in an open-hole specimen, all showing close agreement. These results demonstrate that embedding reduced-time physics into a TCN framework not only accelerates training and improves predictive accuracy but also establishes a fundamentally new, thermodynamically anchored constitutive formulation that surpasses the capabilities of traditional phenomenological models and existing ML-based surrogates.

这项工作介绍了一个基于物理信息的时间卷积网络（TCN）的本构建模框架，用于捕获软材料的极端非线性热粘弹性行为，包括高达200%的大循环伸长，温度依赖的粘弹性和mullins型损伤。与传统的Mullins或热粘弹性模型（需要指定硬编码的功能形式并在8-12个实验中校准大量参数）相比，该框架通过因果时间结构定义了应力，损伤和减少时间温度效应的新演化规律。时间-温度叠加通过Williams-Landel-Ferry （WLF）位移因子直接嵌入，使温度成为缩短时间的内在驱动因素，而不是外部附加参数。这使得模型可以连续学习温度-速率-损伤耦合，而无需预先定义解析演化方程。因此，该框架只需要三个训练实验测试，但推广到六个完全看不见的测试，跨越不同的温度，应变率，循环计数和延伸率水平。该模型成功地外推到远远超出训练范围的区域，包括训练中未使用的温度，应变率高出2.5倍，延伸率高出50%，以及明显更长的循环历史。热力学容许性是通过在损失函数中引入克劳修斯-迪昂不等式来提高的，而损伤演化则受到物理原理的约束。由此产生的代理构成了一个新的本构模型，通过物理嵌入序列学习来表达，而不是传统的封闭形式方程。经过训练的模型可通过VUMAT子程序直接在有限元求解器中实现，从而实现复杂几何形状和负载条件下的预测模拟。通过在20%高斯应力噪声下的准确预测，证明了该方法对实验不确定性的鲁棒性。验证包括3个训练案例、6个独立实验测试和一个几何相关的部署示例，其中涉及裸眼样品的循环Mullins损伤，所有这些都显示出密切的一致性。这些结果表明，将简化时间物理嵌入到TCN框架中不仅可以加速训练并提高预测准确性，还可以建立一个全新的、热力学锚定的本构公式，超越传统现象学模型和现有基于ml的替代品的能力。

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引用次数: 0

Surface severe plastic deformation-enabled deformation behavior control and mechanical property enhancement in metastable ferrous medium-entropy alloys 亚稳亚铁中熵合金表面剧烈塑性变形的变形行为控制与力学性能增强

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-12-13 DOI: 10.1016/j.ijplas.2025.104581

Gang Hee Gu , Sang Guk Jeong , Jae Heung Lee , Stefanus Harjo , Wu Gong , Auezhan Amanov , Jae Wung Bae , Hyeonseok Kwon , Hyoung Seop Kim

Stacking fault energy (SFE) is an intrinsic property that governs the deformation behavior of metallic materials, including dislocation slip, deformation twinning, and phase transformation. In this study, we present a mechanistic perspective demonstrating that the ‘apparent’ SFE and the associated deformation behavior can be tailored by modifying only the localized microstructure (∼100 μm from the surface) through the application of surface severe plastic deformation. This process generates a well-defined gradient microstructure in the near-surface region through grain refinement and an increase in dislocation density. The reduction in apparent SFE induced by localized gradient structure enhances the driving force for martensitic transformation compared to its homogeneous counterpart. This effect originates from the preferential martensite nucleation sites provided by the localized gradient region, as well as from dynamic stress partitioning facilitated by phase interfaces and gradient heterostructure, which synergistically accelerate the growth of martensitic phase. As a result, the deformation behavior was effectively modulated, leading to significantly enhanced mechanical properties. In particular, partial microstructural modification enabled strength enhancement while minimizing the loss of ductility, in clear contrast to conventional approaches based solely on grain refinement or dislocation density enhancement. This work therefore provides phenomenological insight into how localized microstructural engineering can regulate deformation mechanisms and mechanical performance, representing advancements beyond the conventional understanding of mechanical behavior of heterostructured materials.

层错能（SFE）是控制金属材料位错滑移、变形孪晶和相变等变形行为的固有属性。在这项研究中，我们提出了一个机械的观点，证明了“表观”SFE和相关的变形行为可以通过应用表面严重塑性变形来修改局部微观结构（距离表面约100 μm）来定制。该过程通过晶粒细化和位错密度的增加，在近表面区域产生了明确的梯度显微组织。局域梯度结构引起的表观SFE的降低比均匀结构增强了马氏体相变的驱动力。这种效应源于局部梯度区提供的马氏体优先形核位置，以及相界面和梯度异质结构促进的动态应力分配，两者协同促进了马氏体相的生长。结果表明，变形行为得到有效调节，力学性能得到显著提高。特别是，局部的显微组织修饰能够在最大限度地减少延性损失的同时增强强度，这与仅基于晶粒细化或位错密度增强的传统方法形成鲜明对比。因此，这项工作为局部微结构工程如何调节变形机制和机械性能提供了现象学的见解，代表了对异质结构材料力学行为的传统理解之外的进步。

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引用次数: 0

Dislocation-interface interdependent twinning and sequential kinking deformation in fully lamellar Ti alloys fabricated by additive manufacturing 增材制造全层状钛合金的位错-界面相互孪晶和顺序扭结变形

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-12-09 DOI: 10.1016/j.ijplas.2025.104580

Guoqiang Zhu , Baoxian Su , Botao Jiang , Liang Wang , Yupu Cheng , Wuxin Fan , Jiachen Zhou , Hao Guo , Chao Xu , Yanqing Su

With advancements in aerospace, superconducting technology, and advanced propulsion systems, the demand for cryogenic structural materials has become more stringent. Titanium alloys, known for the merits of lightweight and high strength, are promising candidates for such applications. Compared with other microstructural morphologies, the fully lamellar microstructure is recognized for its exceptional cryogenic ductility, which is primarily attributed to the nucleation and propagation of deformation twins. Although the role of α/β interfaces in plastic deformation is widely acknowledged, their potential effects on deformation behavior have yet to be fully elucidated. This work investigates microscale deformation mechanisms, which is associated with interface-mediated deformation modes. The fully lamellar Ti6321 alloy developed from Ti6Al4V is entirely composed of large-scale colonies with periodic arrangement of alternating α and β lamellae. The α/β interface is systematically characterized prior to cryogenic deformation, confirming a perfect Burgers Orientation Relationship (BOR) and misfit dislocations between the initial α and β phases. Post-deformation analysis under cryogenic conditions reveals the presence of {1-102} deformation twins and kinked β lamellae. During cryogenic deformation, twin variants with high Schmid factor (SF) emerge first to facilitate plastic accommodation. Notably, twinning can be also triggered in some low-SF twinned colonies that exhibit intense 〈a〉 dislocations, which can be driven by the dissociation of basal 〈a〉 dislocations. Crucially, these twins propagate continuously across multiple β lamellae via a β kinking-assisted mechanism, providing an efficient pathway for strain accommodation. The synergistic effect of α twinning and sequential β phase kinking contributes to alleviate stress localization, dissipating stored plastic energy, thereby strengthening the cryogenic strength and ductility for the fully lamellar Ti alloys.

随着航空航天、超导技术和先进推进系统的发展，对低温结构材料的需求越来越严格。钛合金以轻量化和高强度的优点而闻名，是此类应用的有希望的候选者。与其他微观组织形态相比，全层状微观组织具有优异的低温延展性，这主要归因于变形孪晶的形核和扩展。虽然α/β界面在塑性变形中的作用已得到广泛承认，但它们对变形行为的潜在影响尚未得到充分阐明。这项工作研究了微观尺度的变形机制，这与界面介导的变形模式有关。由Ti6Al4V发育的Ti6321全片层合金完全由α和β片层交替排列的大规模菌落组成。在低温变形之前对α/β界面进行了系统表征，证实了初始α和β相之间存在完美的Burgers取向关系（BOR）和错配位错。低温条件下的变形后分析显示{1-102}变形孪晶和扭结β片层的存在。在低温变形过程中，具有高施密德因子（SF）的孪晶变体首先出现，以促进塑性调节。值得注意的是，在一些低sf孪晶菌落中也可以触发孪晶，这些菌落表现出强烈的< a >位错，这可能是由基底< a >位错的解离驱动的。至关重要的是，这些双胞胎通过β扭结辅助机制在多个β片上连续繁殖，为菌株调节提供了有效途径。α孪晶和连续β相扭结的协同作用有助于缓解应力局部化，耗散储存的塑性能，从而提高全层状钛合金的低温强度和塑性。

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引用次数: 0

Influence of length scale on strengthening and toughening mechanism of Cr-rich precipitates in multi-principal element alloy 长度尺度对多主元素合金中富cr析出相强化增韧机理的影响

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-12-08 DOI: 10.1016/j.ijplas.2025.104578

Weiming Huang , Shuai Shen , Xingliang Pu , Shuaikang Zhou , Xiaoxiao Wang , Qi Xu , Siyu Liu , Zhanghua Gan , Chuandong Wu , Jing Liu

Cr is essential for enhancing corrosion and oxidation resistance in advanced metallic systems. However, high Cr content may promote the formation of coarse Cr-rich phases (e.g. σ phase), which significantly deteriorate the mechanical performance. Currently, a type of nano-sized Cr-rich precipitates was detected with homogeneous distribution and coherent structure in multi-principal element alloys (MPEAs). It was revealed that the carbon addition can promote the precipitation of the σ phase. Besides, metastable coherent Cr-rich phases were precipitated during the annealing process with the size less than 5 nm. Noted that the tensile strength of MPEAs is 1189.6 MPa at 25 °C and 560.0 MPa at 700 °C, benefiting from both precipitation enhancement and coherent interfaces. This unconventional coherent interface originates from the structural instability of the metastable coherent Cr-rich nanoprecipitates. Metastable coherent Cr-rich nanoprecipitates formed during short-term annealing are coherent with the FCC matrix but will transform into stable non-coherent σ phase after long-term thermal exposure. Dislocations can directly shear the coherent Cr-rich nanoprecipitates, thereby contributing to the synergy of its strength and ductility. These findings provide new insights into the design and application of high-Cr multi-component alloys.

在先进的金属体系中，铬是增强抗腐蚀和抗氧化能力所必需的。然而，高Cr含量会促进粗富Cr相（如σ相）的形成，从而显著降低合金的力学性能。目前，在多主元素合金（mpea）中发现了一种分布均匀、结构一致的纳米级富cr析出物。结果表明，碳的加入促进了σ相的析出。退火过程中还析出了尺寸小于5 nm的亚稳富cr相干相。mpea的抗拉强度在25℃时为1189.6 MPa，在700℃时为560.0 MPa，这得益于析出增强和共格界面的双重作用。这种非常规的相干界面源于亚稳相干富cr纳米沉淀物的结构不稳定性。在短期退火过程中形成的亚稳相干富cr纳米沉淀与FCC基体相一致，但在长期热暴露后会转变为稳定的非相干σ相。位错可以直接剪切相干富cr纳米沉淀物，从而促进其强度和延展性的协同作用。这些发现为高铬多组分合金的设计和应用提供了新的思路。

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引用次数: 0

Phase transformation kinetics model for metals 金属相变动力学模型

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-12-06 DOI: 10.1016/j.ijplas.2025.104579

Daniel N. Blaschke, Abigail Hunter, Dean L. Preston

We develop a new model for phase transformation kinetics in metals by generalizing the Levitas–Preston (LP) phase field model of martensite phase transformations (see Levitas and Preston (2002a,b) and Levitas et al. (2003)) to arbitrary pressure. Furthermore, we account for and track: the interface speed of the pressure-driven phase transformation, properties of critical nuclei, as well as nucleation at grain sites and on dislocations and homogeneous nucleation. The volume fraction evolution of each phase is described by employing KJMA (Kolmogorov, 1937; Johnson and Mehl, 1939; Avrami, 1939, 1940, 1941) kinetic theory. We then test our new model for iron under ramp loading conditions and compare our predictions for the

α \to ϵ

iron phase transition to experimental data of Smith et al. (2013). More than one combination of material and model parameters (such as dislocation density and interface speed) led to good agreement of our simulations to the experimental data, thus highlighting the importance of having accurate microstructure data for the sample under consideration.

通过将马氏体相变的Levitas - Preston （LP）相场模型（见Levitas and Preston （2002a,b）和Levitas etal .(2003)）推广到任意压力，我们开发了一个新的金属相变动力学模型。此外，我们解释和跟踪：压力驱动相变的界面速度，临界核的性质，以及晶粒位置的形核和位错和均匀形核。采用KJMA （Kolmogorov, 1937; Johnson and Mehl, 1939; Avrami, 1939, 1940, 1941）动力学理论描述各相的体积分数演化。然后，我们在斜坡加载条件下测试我们的新铁模型，并将我们对α→ε铁相变的预测与Smith等人（2013）的实验数据进行比较。多种材料和模型参数（如位错密度和界面速度）的组合导致我们的模拟与实验数据很好地一致，从而突出了对所考虑的样品拥有准确的微观结构数据的重要性。

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引用次数: 0

Tailoring dislocation structure and constructing coherent Y2Ti2O7 and Laves stacking faults in 9Cr ODS alloys: A multiple strategy to enhance the strength and ductility 在9Cr ODS合金中调整位错结构和构建一致的Y2Ti2O7和Laves层错：提高强度和塑性的多种策略

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-12-05 DOI: 10.1016/j.ijplas.2025.104577

Mingsheng Yang, Jikang Li, Shengjie Dong, Zhichen Wang, Tong Liu

Simultaneously enhancing strength and ductility poses a significant challenge in 9Cr oxide dispersion strengthened (ODS) ferritic-martensitic (F-M) alloys. In this work, we propose a novel strategy combining Al-Si co-alloying with direct addition of Y₂Ti₂O₇ nanoparticles (YTO NPs), and then employing one-step quenching without tempering heat treatment to simultaneously tailor dislocation structure and construct coherent YTO NPs as well as Laves phase stacking faults (SFs) in 9Cr ODS F-M alloys. Our study reveals that adjusting Al/Si content can optimize martensite volume fraction and aspect ratio, and YTO NPs can suppress dislocation nucleation within the martensitic plane through coherent interface. This synergy mechanism improves strength-ductility via optimizing dislocation density. During deformation, besides the conventional YTO-dislocation mechanism, YTO NPs can simultaneously pin dislocations in different slip systems. Remarkably, YTO NPs can also induce the dual formation of dislocation loops and dipoles, which will inhibit the formation of axial cracks. Moreover, the precipitation of ∼100 nm Laves phases in matrix (BCC) creates deformable zones that evolve into Laves SFs, ultimately improving strength-ductility synergy. 1.5Al1Si alloy (1.5 wt% Al and 1 wt% Si) aligns with the Kocks-Mecking model, where YTO NPs and Laves SFs simultaneously enhance dislocation storage capacity (θ₀) while Laves SFs suppressing dynamic recovery (K), consequently improving work hardening rate. Finally, 1.5Al1Si alloy exhibits up to 1.2 GPa ultimate tensile strength (R_m) while maintaining 8.4 % of total extension at maximum force (A_gt). This study proposes a new strategy to enhance the strength and ductility of ODS alloys.

同时提高9Cr氧化物弥散强化（ODS）铁素体-马氏体（F-M）合金的强度和延展性是一项重大挑战。在这项工作中，我们提出了一种新的策略，将Al-Si共合金化与直接添加Y2Ti2O7纳米颗粒（YTO NPs）相结合，然后采用一步淬火而不回火热处理，同时调整9Cr ODS F-M合金的位错结构，构建一致的YTO NPs和Laves相层错（SFs）。研究表明，调整Al/Si含量可以优化马氏体体积分数和纵横比，YTO NPs可以通过共格界面抑制马氏体平面内的位错形核。这种协同机制通过优化位错密度来提高强度-塑性。在变形过程中，除了传统的YTO位错机制外，YTO NPs还可以同时在不同滑移体系中钉住位错。值得注意的是，YTO NPs还可以诱导位错环和偶极子的双重形成，从而抑制轴向裂纹的形成。此外，基体（BCC）中~ 100 nm Laves相的析出产生了可变形区，这些变形区演变成Laves SFs，最终提高了强度-延性协同作用。1.5 al1si合金（1.5 wt% Al和1 wt% Si）符合Kocks-Mecking模型，其中YTO NPs和Laves SFs同时增强了位错存储容量（θ0），而Laves SFs抑制了动态恢复(K)，从而提高了加工硬化率。最后，1.5Al1Si合金表现出高达1.2 GPa的极限抗拉强度（Rm），同时在最大力（Agt）下保持8.4%的总拉伸。本研究提出了一种提高ODS合金强度和延展性的新策略。

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引用次数: 0

Quantifying deformation heterogeneity of phase boundary and grain boundary in (α+γ) dual phase steel on the basis of slip transfer behavior 基于滑移传递行为量化（α+γ）双相钢相界和晶界变形的非均匀性

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-12-05 DOI: 10.1016/j.ijplas.2025.104575

Wenbin Zhang , Wei Zeng , Can Wang , Miao Jin , Wenzhen Xia , Shiyan Zhao , Zhenyi Huang , Lei Chen , Shuaishuai Liu

The deformation heterogeneity at the grain scale of a ferrite (α) + austenite (γ) dual phase steel was quantitatively investigated based on the slip deformation behavior between adjacent grains. A slip transfer parameter (k_tf), formulated from multi-slip systems and slip rates of activated slip systems, was developed to quantify deformation heterogeneity at grain boundaries and phase boundaries. This parameter exhibits an inverse relationship with deformation heterogeneity, meaning that lower k_tf values signify a greater severity of deformation heterogeneity. This investigation examines the influence of crystallographic orientation relationships and stress states on fundamental characteristics of slip transfer behavior at phase boundaries and grain boundaries. During tension-to-shear deformation, k_tf exhibits a non-monotonic response, characterized by an initial decrease followed by improvement with increasing shear strain. Under balanced 1:1 tension-shear loading conditions, where the boundary normal is oriented at 45° to the principal stress direction, k_tf reaches its minimum value. Furthermore, k_tf demonstrates a general reduction trend with increasing misorientation. Concerning the significant influence of the rotation axis of intergranular orientation relationship, k_tf exhibits systematically lower values when this axis is more closely aligned with the principal stress direction. Coupled in-situ EBSD characterization and crystal plasticity finite element model (CPFEM) of representative volume element (RVE) models confirm that phase boundaries exhibit the lowest k_tf values and most severe deformation heterogeneity. This promotes systematic activation of secondary slip systems in austenite region adjacent to phase boundaries. This slipping response triggers abrupt increases in k_tf followed by accelerated rates, enhancing deformation accommodation capability. The research findings contribute to a more profound comprehension of the heterogeneous deformation mechanism in duplex materials.

基于相邻晶粒间的滑移变形行为，定量研究了铁素体(α) +奥氏体（γ）双相钢在晶粒尺度上的变形不均匀性。根据多滑移系统和激活滑移系统的滑移速率，建立了滑移传递参数（ktf），以量化晶界和相界的变形非均质性。该参数与变形非均质性呈反比关系，即ktf值越低，表明变形非均质性越严重。本研究考察了晶体取向关系和应力状态对相界和晶界滑移转移行为基本特征的影响。在拉伸-剪切变形过程中，ktf表现出非单调响应，其特征是随着剪切应变的增加，ktf初始减小，随后增大。在1:1平衡拉剪加载条件下，边界法线与主应力方向呈45°方向时，ktf达到最小值。此外，ktf随错误定向的增加而普遍降低。晶间取向关系的旋转轴影响显著，当旋转轴与主应力方向更接近时，ktf值有系统地降低。耦合原位EBSD表征和代表性体积元（RVE）模型的晶体塑性有限元模型（CPFEM）证实，相界表现出最低的ktf值和最严重的变形非均质性。这促进了邻近相界的奥氏体区域的二次滑移系统的系统激活。这种滑动响应触发ktf突然增加，随后加速速率，增强变形调节能力。研究结果有助于更深入地理解双相材料的非均质变形机理。

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引用次数: 0

Reasons for abnormal difference in temperature-dependent strain hardening and ductility between additively manufactured CoCrNi and CoCrFeMnNi CoCrNi和CoCrFeMnNi在温度相关应变硬化和塑性方面异常差异的原因

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-12-04 DOI: 10.1016/j.ijplas.2025.104576

Xiaofeng Yang , Tiwen Lu , Xiyu Chen , Ning Yao , Bingbing Wan , Jinqiang Shi , Binhan Sun , Xian-Cheng Zhang , Shan-Tung Tu

Chemical micro-segregations in additively manufactured (AM) materials bring a challenge for their cryogenic applications. The cryogenic mechanical properties of medium/high-entropy alloys (MEA/HEAs) processed by AM MEA/HEAs need more attention. In this work, the same AM parameters resulted in obvious difference in elemental segregation and grain heterogeneity between AM CoCrNi MEA and CoCrFeMnNi HEA, which generated unusual temperature-dependent strain hardening and ductility: First, although the strength and strain hardening of MEA were always higher than those of HEA, the gaps gradually decreased when the temperature decreased from 293 K to 5 K. It was related to solidification parameters, i.e., higher cooling rate and shallower melt depths in MEA, leading to more fine grains. Higher grain heterogeneity in MEA suppressed its deformation twinning (DT) behavior and thereby degrades the hardening capacity at cryogenic temperatures. Secondly, two materials showed an opposite tendency in the temperature-dependent ductility. MEA presented ductility loss at the cryogenic temperature range while HEA displayed an increased ductility. When temperature is 5 K, the ductility of HEA even surpassed MEA. Fracture behavior and molecular dynamics imply that the Cr segregation in MEA reduces the grain boundaries (GBs) cohesive strength, together local stress concentration at the GBs induced by high-density DTs, resulting in the presence of intergranular cracks at cryogenic temperatures. Our work provides an example for strong microstructure-dependent mechanical performance of AM alloys served for harsh environments.

增材制造（AM）材料中的化学微分离给其低温应用带来了挑战。增材制造中/高熵合金（MEA/HEAs）的低温力学性能值得关注。在相同的AM参数下，AM CoCrNi MEA和CoCrFeMnNi HEA在元素偏析和晶粒非均质性方面存在明显差异，从而产生了异常的温度依赖性应变硬化和塑性：首先，虽然MEA的强度和应变硬化始终高于HEA，但当温度从293 K降至5 K时，两者的差距逐渐减小；这与凝固参数有关，即在MEA中，较高的冷却速率和较浅的熔体深度导致晶粒更细。MEA中较高的晶粒非均质性抑制了其变形孪晶（DT）行为，从而降低了其低温硬化能力。其次，两种材料的塑性随温度变化的趋势相反。低温范围内，MEA呈现延展性损失，HEA呈现延展性增加。当温度为5 K时，HEA的延展性甚至超过了MEA。断裂行为和分子动力学表明，低温下MEA中Cr的偏析降低了晶界内聚强度，同时高密度DTs在晶界处引起局部应力集中，导致晶间裂纹的存在。我们的工作为在恶劣环境中使用的AM合金提供了一个强大的微观结构依赖的机械性能的例子。

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引用次数: 0