International Journal of Plasticity最新文献_第8页

Molecular dynamics study on the multi-spallation of Ti-6Al-4V titanium alloy caused by non-planar effect of shock wave induced by microscopic interface 微观界面引起的非平面激波效应对Ti-6Al-4V钛合金多重裂裂的分子动力学研究

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2026-01-01 Epub Date: 2025-11-05 DOI: 10.1016/j.ijplas.2025.104542

Qianhua Yang , Yang Yang , Binwen Wang , Yupei Guo , Xiang Chen

The shock-induced multi-spall processes of nanocrystalline titanium alloys were simulated based on molecular dynamics method in this study to reveal the multi-spall damage mechanism caused by non-planar effect of shock wave induced by microscopic interface. The microscopic interface in nanocrystalline titanium alloys caused non-planar effect of shock wave propagation and hindered shock wave propagation. The shapes of non-planar shock wave in nanocrystalline dual-phase titanium alloys were affected by the distribution of second phase grain. Based on the relationship between the evolution law of tensile stress and the nucleation principle of multi-spall voids, it was found that the multi-spall voids nucleated at microscopic interface under tensile stress generated by the encounter between the secondary reflected wave and the reflected wave for the first time. The non-uniform distribution of tensile stress generated by the encounter between the non-uniform propagation reflected waves led to the non-uniform distribution of multi-spall voids at microscopic interface. The increase of dislocation density caused by second phase grain hindered the secondary void nucleation in nanocrystalline dual-phase titanium alloys, resulting in the difference in secondary void nucleation between nanocrystalline single-phase titanium alloy and nanocrystalline dual-phase titanium alloys. The damage rate (

\dot{D}

) at the spall stage and strain rate (

\dot{ε}

) at the shock stage were positively correlated and followed the relationship:

\dot{D} = a {\dot{ε}}^{b}

(

a

and

b

were fitting parameters and related to the microstructure of material and shock conditions). The multi-voids still nucleated at microscopic interfaces and the intergranular spall occurred in nanocrystalline titanium alloys although the shock velocity increased.

本研究基于分子动力学方法对纳米晶钛合金的冲击诱导多裂过程进行了模拟，揭示了微观界面诱导的非平面激波效应引起的多裂损伤机理。纳米晶钛合金的微观界面对激波的传播产生非平面效应，对激波的传播产生阻碍。纳米晶双相钛合金中第二相晶粒的分布影响了非平面激波的形状。基于拉应力演化规律与多片孔洞成核原理的关系，首次发现在二次反射波与反射波相遇产生的拉应力作用下，多片孔洞在微观界面处成核。非均匀传播反射波相遇产生的拉应力的非均匀分布导致微观界面处多小孔隙的非均匀分布。第二相晶粒引起的位错密度增大阻碍了纳米晶双相钛合金的二次空洞形核，导致纳米晶单相钛合金与纳米晶双相钛合金的二次空洞形核存在差异。剥落阶段的损伤率（D˙）与冲击阶段的应变率（ε˙）呈正相关，并遵循如下关系：D˙=aε˙b （a和b为拟合参数，与材料的微观结构和冲击条件有关）。随着冲击速度的增加，纳米晶钛合金在微观界面处仍存在多孔洞形核，并出现晶间剥落。

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引用次数: 0

Micromechanical analysis of stress-induced anisotropic frictional damage, spontaneous localization and post-peak snapback problem in quasi-brittle geomaterials 准脆性岩土材料应力诱导各向异性摩擦损伤、自发局部化及峰后弹回问题的细观力学分析

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2026-01-01 Epub Date: 2025-11-15 DOI: 10.1016/j.ijplas.2025.104549

Qi-Zhi Zhu , Qiao-Juan Yu , Jian-fu Shao , Xing-Guang Zhao

Some fundamental issues in quasi-brittle solids, such as closed-form failure description, reliable solution to anisotropic coupling equations, cracking-induced localization, post-peak mechanical response, still remain largely open. Focus here is transferred from the case of isotropic damage to more complex anisotropic frictional damage problems. The constitutive equations are formulated by applying linear homogenization to a solid matrix-microcracks heterogeneous system, whose solution actually constitutes a typical nonlinear complementary problem. Analytical solutions are found under some specific loading paths, which make it possible to perform relevant critical analyses on mechanical behaviors of quasi-brittle solid. It is interestingly found that cracks in critical families propagate predominantly, especially in the post-peak phase, by controlling material failure and leading to the localization from diffuse damage (microcracks) to one or several macro cracks. When solids tend to be brittle, there will appear a transition in mechanical response from type-I to type-II with a snap-back phase. On numerical aspects, both fully coupled- and decoupled correction schemes are developed and compared to the analytical results achieved herein.

准脆性固体的一些基本问题，如封闭型破坏描述、各向异性耦合方程的可靠解、裂纹局部化、峰后力学响应等，仍有很大的开放性。这里的重点从各向同性损伤的情况转移到更复杂的各向异性摩擦损伤问题。将线性均匀化方法应用于固体基质-微裂纹非均质系统的本构方程，该系统的解实际上是一个典型的非线性互补问题。在某些特定加载路径下找到了解析解，为准脆性固体力学行为的相关临界分析提供了可能。有趣的是，通过控制材料失效并导致从弥漫性损伤（微裂纹）局部化到一个或几个宏观裂纹，关键族裂纹主要扩展，特别是在峰后阶段。当固体趋于脆性时，力学响应会出现由i型向ii型的转变，并出现回弹阶段。在数值方面，提出了完全耦合和解耦的校正方案，并与本文的解析结果进行了比较。

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引用次数: 0

Nonlinear chemomechanical modeling of hydrogen diffusion in super duplex stainless steel and comparison with x-ray diffraction measurements 超级双相不锈钢中氢扩散的非线性化学力学建模及与x射线衍射测量的比较

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2026-01-01 Epub Date: 2025-11-11 DOI: 10.1016/j.ijplas.2025.104546

David Lindblom , Menghao Liu , Jinshan Pan , Robin Woracek , Carl F.O. Dahlberg

A coupled hydrogen (H) diffusion and higher-order strain gradient plasticity model is used to predict H localization in the ferrite (

α

) and austenite (

γ

) phases of super duplex steel under plane stress conditions. The geometry and finite element (FE) mesh are derived from optical micrograph images of the phase morphology, ensuring a realistic representation of the alloy’s microstructure. The model highlights the role of individual phases in coupled diffusion–mechanics interactions and demonstrates that the phase morphology significantly impacts the localization of H in the material. The results indicate that plastic strains in the ferrite phase exert a much greater influence on the spatial distribution of H than in the austenite phase. Finally, results of the model compare well with in situ X-ray diffraction (XRD) measurements of the temporal evolution of the strain induced by H charging. These findings provide valuable insight for future alloy design strategies aimed at mitigating H localization and preventing embrittlement.

采用氢(H)扩散和高阶应变梯度塑性耦合模型预测了平面应力条件下超级双相钢铁素体（αα）和奥氏体（γγ）相中H的局部化。几何和有限元（FE）网格来源于相形态的光学显微图像，确保了合金微观结构的真实表现。该模型强调了单个相在耦合扩散力学相互作用中的作用，并表明相形态显著影响H在材料中的局部化。结果表明，铁素体相的塑性应变对H的空间分布的影响远大于奥氏体相。最后，该模型的结果与原位x射线衍射（XRD）测量的H电荷引起的应变的时间演变结果进行了比较。这些发现为未来旨在减轻H局部化和防止脆化的合金设计策略提供了有价值的见解。

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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 : 2026-01-01 Epub 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

A cohesive law-based fracture phase field model for microcrack initiation and propagation in shape memory alloys subjected to a cyclic loading 基于内聚规律的形状记忆合金微裂纹萌生与扩展断裂相场模型

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2026-01-01 Epub Date: 2025-11-23 DOI: 10.1016/j.ijplas.2025.104557

Junyuan Xiong , Bo Xu , Jiachen Hu , Chao Yu , Guozheng Kang

This study proposes a cohesive law-based fracture phase field model combined with crystal plasticity theory to elucidate the complex microcrack initiation and propagation of shape memory alloys (SMAs) subjected to cyclic loading. A traction-separation relationship that can be experimentally calibrated is incorporated into the cohesive law of the proposed model, and the degradation of the fracture toughness caused by the localized accumulation of plastic deformation (captured by the crystal plasticity theory) is quantified through a degradation function. The simulation results demonstrate that the relatively high localized accumulated plasticity (leading to a damage accumulation) and elastic energy (providing the main driving force) can lead to microcrack initiation and propagation in NiTi SMAs during cyclic loading. When both the accumulated plasticity and elastic energy are relatively high in a local region, the propagation rate of microcracks in such a region is significantly higher than that of the microcracks in other regions or with only one dominant factor (e.g., accumulated plasticity or elastic energy). The different microstructural evolutions of austenitic and martensitic NiTi SMAs induce distinct distributions and magnitudes of elastic energy and accumulated plasticity, which drive their different microcrack evolutions. The synergistic influence of elastic energy and accumulated plasticity on microcrack evolution is effectively described by the proposed model. The simulated microcrack evolution features are in qualitative agreement with the corresponding experimental results of NiTi SMAs, validating the rationality of the proposed model and providing solid support for the investigation of the crack behavior and fracture-resistant design of SMAs and their devices.

结合晶体塑性理论，提出了基于内聚规律的断裂相场模型来解释形状记忆合金在循环载荷作用下的复杂微裂纹萌生和扩展过程。将可通过实验标定的牵引-分离关系纳入该模型的内聚规律，并通过退化函数量化由局部塑性变形积累引起的断裂韧性退化（由晶体塑性理论捕获）。模拟结果表明，在循环加载过程中，较高的局部累积塑性（导致损伤累积）和弹性能（提供主要驱动力）是导致NiTi sma微裂纹萌生和扩展的主要原因。当某一局部区域的累积塑性和弹性能都较高时，该区域的微裂纹扩展速率明显高于其他区域的微裂纹扩展速率，或者只有一个主导因素（如累积塑性或弹性能）的微裂纹扩展速率明显高于其他区域。奥氏体和马氏体NiTi sma的不同组织演化导致其弹性能和累积塑性的不同分布和大小，从而驱动其不同的微裂纹演化。该模型有效地描述了弹性能和累积塑性对微裂纹演化的协同影响。模拟的微裂纹演化特征与相应的NiTi SMAs实验结果在定性上一致，验证了所提模型的合理性，为SMAs及其器件的裂纹行为研究和抗断裂设计提供了坚实的支撑。

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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 : 2026-01-01 Epub 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

A flux boundary condition for grain boundary-dislocation interaction using all-dislocation density dynamics (ADD) 基于全位错密度动力学（ADD）的晶界-位错相互作用的通量边界条件

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2026-01-01 Epub Date: 2025-11-20 DOI: 10.1016/j.ijplas.2025.104554

Alireza Kalaei , Jinxin Yu , Jian Han , David J. Srolovitz , Alfonso H.W. Ngan

Grain boundaries (GBs) play a crucial role in the plasticity of polycrystalline materials, yet mesoscopic simulation methods to study their effects remain scarce. During plastic deformation, dislocations interact with GBs in various ways—they may transfer to adjacent grains, reflect back, or be absorbed—depending on the GB's properties. Past attempts to understand these effects have predominantly relied on atomistic simulation with limited spatiotemporal scales. Here, we exploit an "all-dislocation" density (ADD) dynamics framework to simulate plasticity within grains and at GBs. We derived a flux boundary condition for ADD that incorporates the dislocation density flux at the GB and implements it numerically on a rhombus mesh structure. The dislocation flux is computed using a mathematically robust framework that rigorously accounts for factors affecting slip transfer. The numerical scheme examines the effects of misorientation angle and grain size on slip transfer under constant stress, constant stress rate, and constant strain rate conditions. The results reveal that lower misorientation angles lead to higher plastic strain and mobile dislocation density. Furthermore, plastic strain is inversely proportional to the square root of the grain size, aligning with the Hall–Petch relationship. Strain hardening intensifies with increasing grain boundary misorientation, reflecting reduced slip transfer through less permeable boundaries. The study also investigates how mobility and initial dislocation density influence lattice resistance and GB strengthening, revealing transitions between hardening mechanisms. These expected results confirm that the ADD framework is appropriate for mesoscopic simulation of GB effects in dislocation plasticity.

晶界在多晶材料的塑性中起着至关重要的作用，但研究其影响的介观模拟方法仍然很少。在塑性变形过程中，位错以各种方式与GB相互作用——它们可能转移到相邻的晶粒，反射回来，或被吸收——这取决于GB的性能。过去理解这些效应的尝试主要依赖于有限时空尺度的原子模拟。在这里，我们利用“全位错”密度（ADD）动力学框架来模拟晶粒内和gb的塑性。我们推导了一个包含位错密度通量的ADD通量边界条件，并在菱形网格结构上数值实现了它。位错通量的计算采用了数学上稳健的框架，严格考虑了影响滑移传递的因素。该数值方案考察了在恒定应力、恒定应力速率和恒定应变速率条件下，取向角和晶粒尺寸对滑移传递的影响。结果表明，取向角越小，塑性应变和可动位错密度越高。此外，塑性应变与晶粒尺寸的平方根成反比，符合Hall-Petch关系。应变硬化随着晶界取向偏差的增加而加剧，反映出通过渗透性较低的晶界的滑移传递减少。研究还探讨了迁移率和初始位错密度如何影响晶格电阻和GB强化，揭示了硬化机制之间的转变。这些预期结果证实了ADD框架适用于位错塑性中GB效应的介观模拟。

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引用次数: 0

A non-isothermal fractional consistency two-surface viscoplasticity model for gas hydrate-bearing sediments 含天然气水合物沉积物非等温分数稠度双表面粘塑性模型

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2026-01-01 Epub Date: 2025-11-10 DOI: 10.1016/j.ijplas.2025.104547

Wei Cheng, Zhen-Yu Yin

Gas hydrate-bearing sediments (GHBS), recognized as an emerging and highly promising unconventional energy resource, exhibit pronounced rate-, temperature-, and pore pressure-dependent mechanical behaviors that have been inadequately addressed or frequently overlooked in existing constitutive modeling frameworks. In this paper, a novel non-isothermal two-surface elasto-viscoplastic model is proposed based on the fractional consistency viscoplasticity and bounding surface theory to capture the key mechanical behaviors of GHBS under varying loading conditions. Specifically, a modified isotach viscosity formulation is first extended to account for hydrate conditions, with the creep coefficient expressed as an exponential function of hydrate saturation. Secondly, a two-surface (loading and yield surfaces) framework is formulated, integrating multifactorial viscoplastic hardening mechanisms, namely isotropic hardening, progressive hardening, and deviatoric degradation, along with a Caputo-formed non-orthogonal viscoplastic flow rule. Then, employing the consistency condition of the loading surface, an incremental constitutive relation is rigorously formulated to explicitly relate stress, strain, strain rate, temperature, pore pressure, and hydrate saturation. Finally, validation against experimental data demonstrates the model’s excellent capability to simulate mechanical behaviors under complex time-dependent stress paths. This robust, rate-dependent constitutive framework provides a fundamental basis for subsequent advancements aimed at incorporating a broader spectrum of pertinent factors, such as hydrate dissociation, extended temperature ranges, multi-component effects, and particle crushing, etc.

天然气水合物沉积物（GHBS）被认为是一种新兴的、非常有前途的非常规能源资源，它表现出明显的速率、温度和孔隙压力相关的力学行为，这些行为在现有的本构模型框架中没有得到充分的解决，或者经常被忽视。本文基于分数一致性粘塑性和边界面理论，提出了一种新的非等温双面弹粘塑性模型，以捕捉不同加载条件下GHBS的关键力学行为。具体来说，首先将修正的等黏度公式推广到水合物条件，将蠕变系数表示为水合物饱和度的指数函数。其次，建立了两面（加载面和屈服面）框架，整合了各向同性硬化、渐进硬化和偏差退化等多因素粘塑性硬化机制，以及caputo形成的非正交粘塑性流动规律。然后，利用加载面一致性条件，严格建立增量本构关系，明确地将应力、应变、应变率、温度、孔隙压力和水合物饱和度联系起来。最后，对实验数据的验证表明，该模型具有良好的能力，可以模拟复杂的随时间变化的应力路径下的力学行为。这种稳健的、速率相关的本构框架为随后的进展提供了基础，旨在纳入更广泛的相关因素，如水合物解离、延长的温度范围、多组分效应和颗粒破碎等。

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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 : 2026-01-01 Epub 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

Experimental study and micromechanics-based general constitutive theoretical framework for cold-region rocks under triaxial compression 寒区岩石三轴压缩试验研究及基于细观力学的一般本构理论框架

IF 12.8 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-12-01 Epub Date: 2025-10-10 DOI: 10.1016/j.ijplas.2025.104499

Wenlin Wu , Yuanming Lai , Mingyi Zhang , Xiangtian Xu , Wansheng Pei , Ruiqiang Bai , Jing Zhang , Yanyan Chen

This study establishes a general multiscale constitutive model by integrating micromechanics, thermodynamics, and fractional calculus theory for cold-region rocks under triaxial compression. Conventional triaxial compression tests are conducted on frozen and freeze-thawed rock samples to investigate the macroscopic mechanical properties under the influence of freezing temperature and freeze-thaw (F-T) cycles. Additionally, scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) analyses provide deeper insights into the intrinsic microscale physical mechanisms. Experimental observations reveal that, at the mesoscale, cold-region rocks can be conceptualized as a composite medium composed of a porous matrix interspersed with cracks. At the microscale, the porous matrix itself consists of mineral grains, pore ice, and unfrozen pore water. By quantitatively characterizing the relevant microstructural variables, a two-step homogenization procedure is employed to derive the effective elastic properties of rocks: the self-consistent scheme (SCS) at the microscale and the Mori–Tanaka (M-T) method at the mesoscale. After rigorously deducing the system’s free energy and corresponding state equations, we systematically establish specific criteria of the model: the loading damage evolution associated with crack initiation and propagation, state-dependent friction-cohesive-type yielding induced plastic distortion, and open cracks closure deformation caused nonlinear and Poisson effect. To accurately capture the characteristics of plastic deformation, the non-orthogonal plastic flow rule (NPFR) formulated via fractional differential calculus is adopted. For efficient numerical implementation, a robust stress integration algorithm is developed by combining the line search method (LSM) with conventional return mapping (RM) algorithm. The predictive performance of the proposed model is thoroughly validated through the frozen and F-T red sandstone and granite.

结合细观力学、热力学和分数阶微积分理论，建立了寒区岩石在三轴压缩下的通用多尺度本构模型。采用常规三轴压缩试验对冻结和冻融岩样进行压缩试验，研究冻结温度和冻融循环对岩石宏观力学性能的影响。此外，扫描电子显微镜（SEM）和核磁共振（NMR）分析提供了对内在微观物理机制的更深入了解。实验观测表明，在中尺度上，寒冷地区的岩石可以被定义为一种由多孔基质和裂缝组成的复合介质。在微观尺度上，多孔基质本身由矿物颗粒、孔隙冰和未冻结孔隙水组成。通过定量表征相关微观结构变量，采用两步均匀化方法推导岩石的有效弹性特性：微观尺度上的自洽方案（SCS）和中尺度上的Mori-Tanaka （M-T）方法。在严格推导出系统的自由能和相应的状态方程后，系统地建立了模型的具体准则：与裂纹萌生和扩展相关的加载损伤演化、状态依赖的摩擦-黏结型屈服诱发的塑性变形、开放裂纹闭合变形引起的非线性和泊松效应。为了准确地捕捉塑性变形的特征，采用分数阶微分法推导的非正交塑性流动规则（NPFR）。为了高效的数值实现，将直线搜索法（LSM）与常规的返回映射（RM）算法相结合，提出了一种鲁棒的应力积分算法。通过冻结和F-T红砂岩和花岗岩，彻底验证了该模型的预测性能。

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