International Journal of Plasticity最新文献_第6页

A crystal plasticity-damage coupled finite element framework for predicting mechanical behavior and ductility limits of thin metal sheets

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-02-14 DOI: 10.1016/j.ijplas.2025.104267

S. Zhou, M. Ben Bettaieb, F. Abed-Meraim

A new crystal plasticity finite element (CPFE) approach is developed to predict the mechanical behavior and ductility limits of thin metal sheets. Within this approach, a representative volume element (RVE) is chosen to accurately capture the mechanical characteristics of these metal sheets. This approach uses the periodic homogenization multiscale scheme to ensure the transition between the RVE and single crystal scales. At the single crystal scale, the mechanical behavior is modeled as elastoplastic within the finite strain framework. The plastic flow is governed by a modified version of the Schmid law, which incorporates the effects of damage on the evolution of microscopic mechanical variables. The damage behavior is modeled using the framework of Continuum Damage Mechanics (CDM), introducing a scalar microscopic damage variable at the level of each crystallographic slip system (CSS). The evolution law of this damage variable is derived from thermodynamic forces, resulting in deviations from the normality rule in microscopic plastic flow. This coupling of damage and elastoplastic behavior leads to a highly nonlinear set of constitutive equations. To solve these equations, an efficient return-mapping algorithm is developed and implemented in the ABAQUS/Standard finite element software via a user-defined material subroutine (UMAT). At the macroscopic scale, the onset of localized necking is predicted by the Rice bifurcation theory. The proposed damage-coupled single crystal model and its integration scheme are validated through several numerical simulations. The analysis extensively explores the impact of microstructural and damage parameters on the mechanical behavior and ductility limits of both single crystals and polycrystalline aggregates. The numerical results indicate that both of the mechanical behavior and ductility limits are significantly influenced by the microscopic damage and deviations from normal plastic flow rule.

{"title":"A crystal plasticity-damage coupled finite element framework for predicting mechanical behavior and ductility limits of thin metal sheets","authors":"S. Zhou, M. Ben Bettaieb, F. Abed-Meraim","doi":"10.1016/j.ijplas.2025.104267","DOIUrl":"10.1016/j.ijplas.2025.104267","url":null,"abstract":"<div><div>A new crystal plasticity finite element (CPFE) approach is developed to predict the mechanical behavior and ductility limits of thin metal sheets. Within this approach, a representative volume element (RVE) is chosen to accurately capture the mechanical characteristics of these metal sheets. This approach uses the periodic homogenization multiscale scheme to ensure the transition between the RVE and single crystal scales. At the single crystal scale, the mechanical behavior is modeled as elastoplastic within the finite strain framework. The plastic flow is governed by a modified version of the Schmid law, which incorporates the effects of damage on the evolution of microscopic mechanical variables. The damage behavior is modeled using the framework of Continuum Damage Mechanics (CDM), introducing a scalar microscopic damage variable at the level of each crystallographic slip system (CSS). The evolution law of this damage variable is derived from thermodynamic forces, resulting in deviations from the normality rule in microscopic plastic flow. This coupling of damage and elastoplastic behavior leads to a highly nonlinear set of constitutive equations. To solve these equations, an efficient return-mapping algorithm is developed and implemented in the ABAQUS/Standard finite element software via a user-defined material subroutine (UMAT). At the macroscopic scale, the onset of localized necking is predicted by the Rice bifurcation theory. The proposed damage-coupled single crystal model and its integration scheme are validated through several numerical simulations. The analysis extensively explores the impact of microstructural and damage parameters on the mechanical behavior and ductility limits of both single crystals and polycrystalline aggregates. The numerical results indicate that both of the mechanical behavior and ductility limits are significantly influenced by the microscopic damage and deviations from normal plastic flow rule.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"187 ","pages":"Article 104267"},"PeriodicalIF":9.4,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417678","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

Machine-learning local resistive environments of dislocations in complex concentrated alloys from data generated by molecular dynamics simulations

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-02-13 DOI: 10.1016/j.ijplas.2025.104274

Wei Li , Alfonso H.W. Ngan , Yuqi Zhang

Complex concentrated alloys (CCAs) differ from pure metals and conventional dilute alloys in that the multiple constituent elements are prone to develop special local atomic environments (LAEs). Due to the complexity and spatial variability of the LAEs, the resistance that they offer to travelling dislocations cannot be determined a priori by conventional strengthening theories. In this work, molecular dynamics (MD) simulations of a prototypic CCA of NiCoCr were used to generate data for dislocation features that may potentially affect dislocation resistance. Extensive analysis of these features via their Pearson correlation coefficients with dislocation velocity and ablation studies using light gradient-boosting machine learning (ML) models show that (i) the local planar fault energy (PFE), (ii) local gradient of the PFE, and (iii) dislocation core width, while all prime factors for dislocation resistance, do not have strongly linear correlation with the dislocation velocity. However, reasonably high prediction accuracy (>80 %) is achieved when all three factors are included in the ML model. Furthermore, lattice distortion, a much-discussed strengthening factor for CCAs in the literature, is also not strongly linearly correlated and its effect can be well represented by the PFE. These results indicate that CCA strength is governed not by individual dislocation-resistance factors, but a synergistic combination of these factors that goes beyond any a priori assumption. This work highlights the complexity in the nature of CCA strength, and the suitability and success of machine learning as an a posteriori approach for understanding it.

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引用次数: 0

Mitigating embrittlement of sigma phase in dual-phase high-entropy alloys through heterostructure design

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-02-07 DOI: 10.1016/j.ijplas.2025.104272

Sihao Zou , Chunyu Dong , Xiaodong Tan , Zhiyuan Liang , Weizong Bao , Binbin He , Wenjun Lu

The design of dual-phase high-entropy alloys (HEAs) often involves extensive alloying, which can lead to the formation of topologically close-packed (TCP) phases, significantly reducing tensile ductility. Balancing the high hardness of TCP phases while minimizing their embrittling effects is crucial for developing high-performance HEAs. This study, which focuses on the brittle sigma phase, proposes an innovative heterogeneous structural coupling design strategy that simultaneously enhances the strengthening effect of the sigma phase while minimizing its embrittlement role. A (FeCoCrNi)₉₀Al₁₀ HEA with sigma phase is employed as the model material, where a bimodal grain heterogeneous structure is achieved through a short-term high-temperature annealing process at 850 °C for 5 min. A small amount of sigma phase precipitates (∼0.8 vol.%) in the recrystallization (RX) region, modulating the hardness difference between the RX and non-recrystallized (NRX) regions. This induces significant heterogeneous deformation-induced (HDI) stress, while promoting coordinated deformation between regions, thereby triggering continuous work hardening and plastic deformation. As a result, the HEA exhibits an exceptional combination of high strength (1412 MPa) and ductility (14.9 %). The underlying deformation mechanism involves strain hardening driven by HDI stress, which strengthens the RX region and minimizes local strain mismatch between the sigma phase and the FCC matrix, suppressing the nucleation and propagation of interfacial cracks. The present approach presents a promising pathway for co-designing strength and ductility in metallic materials susceptible to TCP phase formation.

{"title":"Mitigating embrittlement of sigma phase in dual-phase high-entropy alloys through heterostructure design","authors":"Sihao Zou , Chunyu Dong , Xiaodong Tan , Zhiyuan Liang , Weizong Bao , Binbin He , Wenjun Lu","doi":"10.1016/j.ijplas.2025.104272","DOIUrl":"10.1016/j.ijplas.2025.104272","url":null,"abstract":"<div><div>The design of dual-phase high-entropy alloys (HEAs) often involves extensive alloying, which can lead to the formation of topologically close-packed (TCP) phases, significantly reducing tensile ductility. Balancing the high hardness of TCP phases while minimizing their embrittling effects is crucial for developing high-performance HEAs. This study, which focuses on the brittle sigma phase, proposes an innovative heterogeneous structural coupling design strategy that simultaneously enhances the strengthening effect of the sigma phase while minimizing its embrittlement role. A (FeCoCrNi)<sub>90</sub>Al<sub>10</sub> HEA with sigma phase is employed as the model material, where a bimodal grain heterogeneous structure is achieved through a short-term high-temperature annealing process at 850 °C for 5 min. A small amount of sigma phase precipitates (∼0.8 vol.%) in the recrystallization (RX) region, modulating the hardness difference between the RX and non-recrystallized (NRX) regions. This induces significant heterogeneous deformation-induced (HDI) stress, while promoting coordinated deformation between regions, thereby triggering continuous work hardening and plastic deformation. As a result, the HEA exhibits an exceptional combination of high strength (1412 MPa) and ductility (14.9 %). The underlying deformation mechanism involves strain hardening driven by HDI stress, which strengthens the RX region and minimizes local strain mismatch between the sigma phase and the FCC matrix, suppressing the nucleation and propagation of interfacial cracks. The present approach presents a promising pathway for co-designing strength and ductility in metallic materials susceptible to TCP phase formation.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"187 ","pages":"Article 104272"},"PeriodicalIF":9.4,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143367238","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

A meso-scale model to predict flow stress and microstructure during hot deformation of IN718WP

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-02-06 DOI: 10.1016/j.ijplas.2025.104271

Nilesh Kumar , Franz Miller Branco Ferraz , Ricardo Henrique Buzolin , Esmaeil Shahryari , Maria C. Poletti , Surya D. Yadav

This research presents a dislocation-based hot deformation model to address a nickel-based superalloy's flow stress response and discontinuous dynamic recrystallization (DDRX) behavior. The developed model can predict the flow curves and subsequent microstructure evolutions during the hot deformation. The evolution of microstructure-reliant internal variables was predicted and validated thoroughly. Furthermore, the influence of strain rate and temperature on the glide and climb velocities have also been discussed to reveal more insights into the microstructural development. Dislocation density and DDRX fraction predicted from the model was compared with dislocation density and DDRX fraction obtained from electron backscattered diffraction (EBSD) measurements with reasonable matching. Higher temperatures and slower strain rates provide favorable conditions for DDRX in this alloy. The importance of this model relies on its prediction capability in terms of flow curve, mobile and immobile dislocation densities, DDRX fraction, grain size and dislocation velocities. Single set of parameters were obtained from twelve experimental curves and rest of the eleven curves were predicted by the model using those parameters. The present research approach is helpful to predict the multiple flow curves along with the corresponding microstructure evolution in LSFE materials.

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引用次数: 0

Strain-rate and temperature dependent optimum precipitation sizes for strengthening in medium-entropy alloys

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-02-06 DOI: 10.1016/j.ijplas.2025.104268

Ziyi Yuan , Cen Chen , Xu Zhang , Lingling Zhou , Xiaolei Wu , Fuping Yuan

The (FeCoNi)₈₆Al₇Ti₇ medium-entropy alloy (MEA) with varying sizes and fixed volume fraction of coherent L1₂ precipitates was fabricated, and the effects of precipitation size on mechanical properties at varying strain rates and temperatures were investigated experimentally. An optimum precipitation size for precipitation strengthening can be always observed for the experimental curves under different strain rates and temperatures. The dominant precipitation mechanism under dynamic conditions is found to be transited from the dislocation-shearing mechanism to the Orowan dislocation-looping mechanism with increasing precipitation size. A novel theoretical model was developed to consider the effects of strain rate and temperature on the precipitation shearing strengthening and the Orowan looping strengthening. The predicted precipitation strengthening curves as a function of precipitation size by the newly-developed model are observed to be well consistent with the experimental results under different strain rates and temperatures. The optimum precipitation size for the strongest precipitation strengthening is found to be strain-rate and temperature dependent, and shift to higher values with increasing strain rate and decreasing temperature, as predicted by the theoretical model and validated by the experimental results.

{"title":"Strain-rate and temperature dependent optimum precipitation sizes for strengthening in medium-entropy alloys","authors":"Ziyi Yuan , Cen Chen , Xu Zhang , Lingling Zhou , Xiaolei Wu , Fuping Yuan","doi":"10.1016/j.ijplas.2025.104268","DOIUrl":"10.1016/j.ijplas.2025.104268","url":null,"abstract":"<div><div>The (FeCoNi)<sub>86</sub>Al<sub>7</sub>Ti<sub>7</sub> medium-entropy alloy (MEA) with varying sizes and fixed volume fraction of coherent L1<sub>2</sub> precipitates was fabricated, and the effects of precipitation size on mechanical properties at varying strain rates and temperatures were investigated experimentally. An optimum precipitation size for precipitation strengthening can be always observed for the experimental curves under different strain rates and temperatures. The dominant precipitation mechanism under dynamic conditions is found to be transited from the dislocation-shearing mechanism to the Orowan dislocation-looping mechanism with increasing precipitation size. A novel theoretical model was developed to consider the effects of strain rate and temperature on the precipitation shearing strengthening and the Orowan looping strengthening. The predicted precipitation strengthening curves as a function of precipitation size by the newly-developed model are observed to be well consistent with the experimental results under different strain rates and temperatures. The optimum precipitation size for the strongest precipitation strengthening is found to be strain-rate and temperature dependent, and shift to higher values with increasing strain rate and decreasing temperature, as predicted by the theoretical model and validated by the experimental results.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"187 ","pages":"Article 104268"},"PeriodicalIF":9.4,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143258673","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

Attribution of heterogeneous stress distributions in low-grain polycrystals under conditions leading to damage

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-02-03 DOI: 10.1016/j.ijplas.2025.104258

Samuel D. Dunham , Yinling Zhang , Nan Chen , Coleman Alleman , Curt A. Bronkhorst

In high-purity polycrystalline metallic materials, voids tend to favor grain boundaries as nucleation sites due to the elevated stress states produced by granular interactions and the weakened grain boundary from the relative atomic disorder. To quantify the key factors of this elevated stress state, simple compression of a small multi-grain cylinder of body-centered cubic tantalum was simulated using a single crystal plasticity model that incorporates non-Schmid effects. Four increasingly complex synthetic microstructures were created to tractably incorporate grain boundary interactions, and a statistically significant number of combinations were performed by varying the initial crystallographic orientations of the microstructure. Most of these simulations produce the maximum von Mises stress on a grain boundary and less frequently at the multi-grain junctions. To build a statistical model for the maximum von Mises stress at the grain boundary, physically based features that could contribute to the elevated stress state were selected. Then, a learning algorithm based on information theory was used to identify which of these features contributed the most information to the data set. The identified features include a grain’s propensity to accommodate both elastic and plastic deformations and their directional components. The misalignment of the direction of each grain’s mechanical response was found to be strongly correlated to the magnitude of the stress near the grain boundary. For all of the synthetic microstructures, the statistical models produce a residual distribution that is nearly Gaussian with a variance of, at most, 10% of the prior distribution. The successful performance of the statistical model implies the correct identification of the physical features that cause severe stress localization in polycrystalline materials. The statistical models constructed here can be used to formulate a physically motivated void nucleation model which is sensitive to a microstructure’s propensity to produce elevated stress states. These statistical models also enable the design of material microstructures, in which the crystallographic orientation is chosen to resist void nucleation.

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引用次数: 0

A multi-physics model for the evolution of grain microstructure 晶粒微观结构演化的多物理场模型

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-02-01 DOI: 10.1016/j.ijplas.2024.104201

I.T. Tandogan , M. Budnitzki , S. Sandfeld

When a metal is loaded mechanically at elevated temperatures, its grain microstructure evolves due to multiple physical mechanisms. Two of which are the curvature-driven migration of the grain boundaries due to increased mobility, and the formation of subgrains due to severe plastic deformation. Similar phenomena are observed during heat treatment subsequent to severe plastic deformation. Grain boundary migration and plastic deformation simultaneously change the lattice orientation at any given material point, which is challenging to simulate consistently. The majority of existing simulation approaches tackle this problem by applying separate, specialized models for mechanical deformation and grain boundary migration sequentially. Significant progress was made recognizing that the Cosserat continuum represents an ideal framework for the coupling between different mechanisms causing lattice reorientation, since rotations are native degrees of freedom in this setting.

In this work we propose and implement a multi-physics model, which couples Cosserat crystal plasticity to Henry–Mellenthin–Plapp (HMP) type orientation phase-field in a single thermodynamically consistent framework for microstructure evolution. Compared to models based on the Kobayashi–Warren–Carter (KWC) phase-field, the HMP formulation removes the nonphysical term linear in the gradient of orientation from the free energy density, thus eliminating long-range interactions between grain boundaries. Further, HMP orientation phase field can handle inclination-dependent grain boundary energies. We evaluate the model’s predictions and numerical performance within a two-dimensional finite element framework, and compare it to a previously published results based on KWC phase-field coupled with Cosserat mechanics.

当金属在高温下机械加载时，由于多种物理机制，其晶粒微观结构发生了变化。其中两种是由于迁移率增加而引起的曲率驱动的晶界迁移，以及由于严重的塑性变形而形成的亚晶。在严重塑性变形后的热处理过程中也观察到类似的现象。晶界迁移和塑性变形同时改变了任意材料点的晶格取向，这一过程的一致性模拟具有挑战性。现有的大多数模拟方法通过应用单独的、专门的机械变形和晶界迁移模型来解决这个问题。认识到Cosserat连续体代表了导致晶格重定向的不同机制之间耦合的理想框架，这取得了重大进展，因为在这种情况下旋转是固有的自由度。在这项工作中，我们提出并实现了一个多物理场模型，该模型将coserat晶体塑性与Henry-Mellenthin-Plapp （HMP）型取向相场耦合在一个单一的热力学一致的框架中，用于微观结构演化。与基于Kobayashi-Warren-Carter （KWC）相场的模型相比，HMP公式从自由能密度中去除了取向梯度线性的非物理项，从而消除了晶界之间的远程相互作用。此外，HMP取向相场可以处理与倾角相关的晶界能。我们在二维有限元框架内评估了模型的预测和数值性能，并将其与先前发表的基于KWC相场耦合Cosserat力学的结果进行了比较。

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引用次数: 0

Stress-fractional modelling of dilatancy behavior under monotonic loading based on a new yield surface of coarse-grained soil 基于一种新的粗粒土屈服面单调加载下剪胀特性的应力-分数模型

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-02-01 DOI: 10.1016/j.ijplas.2024.104236

Erlu Wu , Wanli Guo , Na Li , Ping Jiang , Wei Wang , Yifei Sun

Fractional calculus has been proven to be a powerful modeling tool for soil, which is often used to develop the dilatancy equation in the model construction. However, the existing fractional-order dilatancy equation incorporating the state parameter has the unsatisfying simulations on the dilatancy behaviors of coarse-grained soil, which strongly depends on the material state, i.e., the stress and void ratio. For that, a new fractional-order dilatancy model incorporating the stress and strain states is developed for coarse-grained soil. Originally, a new yield function applicable to coarse-grained soil is proposed by modifying the yield function of Cam-clay model, in which a parameter controlling the shape of the yield surface is introduced. Then, a fractional-order dilatancy model for coarse-grained soil is derived by using the fractional derivative of the new yield function. Meanwhile, an evolution law for the order of fractional derivative is put forward, which shows the development with the shear strain. Ulteriorly, drained triaxial compression test results of three coarse-grained soils with only one void ratio and two coarse-grained soils with three void ratios are simulated, and it is found that there is a good agreement between the model simulations and test results. Finally, the elastoplastic model developed by incorporating the modified yield function and fractional-order dilatancy model into Cam-clay model is used to simulate the bearing capacity of one foundation, and the result reveals that the introduction of fractional calculus will not encounter convergence issue in finite element analysis.

分数阶微积分已被证明是一种强大的土体建模工具，在模型构建中常用于建立剪胀方程。然而，现有的含状态参数的分数阶剪胀方程对粗粒土的剪胀行为的模拟效果并不理想，这主要取决于材料的状态，即应力与孔隙比。为此，建立了一种考虑应力和应变状态的分数阶剪胀模型。通过对Cam-clay模型的屈服函数进行修正，提出了一种适用于粗粒土的屈服函数，其中引入了一个控制屈服面形状的参数。然后，利用新屈服函数的分数阶导数，建立了粗粒土的分数阶剪胀模型。同时，给出了分数阶导数阶数随剪切应变的演化规律。最后，对3种含1空隙比的粗粒土和2种含3空隙比的粗粒土的排水三轴压缩试验结果进行了模拟，发现模型模拟结果与试验结果吻合较好。最后，将修正屈服函数和分数阶剪胀模型合并到Cam-clay模型中建立的弹塑性模型对单地基承载力进行了模拟，结果表明分数阶微积分的引入不会在有限元分析中遇到收敛问题。

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引用次数: 0

Elucidating the role of combined latent hardening due to slip-slip and slip-twin interaction for modeling the evolution of crystallographic texture in high nitrogen steels 阐明由滑移和滑移孪晶相互作用引起的联合潜在硬化在模拟高氮钢晶体织构演变中的作用

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-02-01 DOI: 10.1016/j.ijplas.2024.104215

Bhanu Pratap Singh, Jyoti Ranjan Sahoo, Sumeet Mishra

A thorough framework for addressing the evolution of crystallographic texture in high nitrogen steels is developed in the present work. The elementary doctrine of the proposed framework is the inclusion of latent hardening due to slip-slip interaction along with slip-twin interaction in the visco-plastic self-consistent (VPSC) model for simulating the evolution of crystallographic texture in high nitrogen steels. The latent hardening due to slip-slip interaction is accounted for by specifying the complete interaction matrix (12 × 12), which allows all possible interactions between different slip systems. The latent hardening due to slip-slip interaction acts in combination with the latent hardening due to slip-twin interaction in raising the deformation resistance of the slip systems, which in turn enhances the propensity of twinning for the orientations along the β-fiber between the ideal Copper and S position. As a result, these β-fiber orientations are destabilized and reorient towards the

α

-fiber orientations in the Euler space. The proposed modeling framework is validated against experimental orientation distribution function sections after different rolling reductions. It was observed that inclusion of the combined latent hardening effect provides a superior agreement with the experimental textures compared to the standard approach of considering only the latent hardening due to slip-twin interaction in low stacking fault energy materials. The modeling work is aptly supported by detailed microstructural characterization involving estimation of twin fraction via X-ray line profile analysis, twin characteristics via transmission electron microscopy and the reorientation caused due to twinning via electron back scatter diffraction.

在本工作中，开发了一个解决高氮钢晶体织构演变的完整框架。所提出的框架的基本原则是在模拟高氮钢晶体织构演变的粘塑性自一致（VPSC）模型中包含由于滑移相互作用和滑移-孪相互作用引起的潜在硬化。通过指定完整的相互作用矩阵（12 × 12）来解释滑移相互作用引起的潜在硬化，该矩阵允许不同滑移系统之间的所有可能的相互作用。滑移-滑移相互作用的潜在硬化与滑移-孪晶相互作用的潜在硬化共同作用，提高了滑移体系的变形抗力，进而增强了理想铜位和S位之间沿β-纤维取向的孪晶倾向。结果，这些β-纤维取向在欧拉空间中不稳定并向α- α-纤维取向重新定向。通过不同滚动约简后的实验取向分布函数截面对所提出的建模框架进行了验证。结果表明，在低层错能材料中，与只考虑滑移-孪晶相互作用的潜在硬化的标准方法相比，考虑联合潜在硬化效应与实验织构的一致性更好。建模工作得到了详细的微观结构表征的支持，包括通过x射线线剖面分析估计孪晶分数，通过透射电子显微镜估计孪晶特征，以及通过电子背散射衍射测量孪晶引起的重定向。

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引用次数: 0

In-situ experiment and numerical modelling of the intragranular and intergranular damage and fracture in plastic deformation of ductile alloys 韧性合金塑性变形中晶内和晶间损伤与断裂的现场实验和数值模拟

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-02-01 DOI: 10.1016/j.ijplas.2024.104217

Wang Cai , Chaoyang Sun , Chunhui Wang , Lingyun Qian , M.W. Fu

In this research, a unified damage indication considering the intragranular and intergranular damage initiation and evolution was developed for studying the damage and fracture behaviours of the excellent ductile alloys represented by TWIP steels, and a cohesive zone model-crystal plasticity finite element method (CZM-CPFEM) approach was developed, where the crystal plasticity with coupled slip and twinning and the strain energy-based damage criterion was employed to reveal the plastic deformation and damage in grain interior (GI), while the quadratic nominal stress (QUADS) and the power law of the CZM were selected to describe the damage and cracking at the grain boundaries (GBs). The stress-strain responses, twin evolutions, damage nucleation and cracking of fine-grained (FG) and fine-/ultrafine-grained (F/UFG) TWIP steels were validated by in-situ SEM/EBSD tensile experiments. The effects of grain size, misorientation angle, grain orientation and initial microvoids on the GI and GB damage and fracture were studied and analysed by combining micromechanical tests and the CZM-CPFEM approach. The results demonstrated that the interaction of deformation mechanisms promoted the preferential initiation of microcracks at GBs and their junctions, while slip bands and twin bundles in GI induced the rapid growth and extension of the localized microcracks, eventually resulting in the mixed fracture mode of intergranular and intragranular cracks. In addition, GB damage was dominant for F/UFG TWIP steels. Increasing grain size can effectively suppress GB damage and increase the proportion of GI damage. Larger misorientation angles can weaken GB properties, while smaller misorientation angles effectively promote strain/stress coordination and delay GI and GB damage. Larger Schmid factors for slip and twinning are favourable for activating dislocations and twins, promoting strain/stress coordination to retard microcrack initiation and improving uniform elongation. Moreover, both initial microvoids can effectively reduce uniform tensile strength (UTS) and fracture strain. Specifically, the microvoids located at GBs and their junctions increase the percentage of GB damage and the possibility of intergranular cracking, especially at the quadruple junctions of GBs.

在这项研究中，为研究以 TWIP 钢为代表的优异韧性合金的损伤和断裂行为，开发了一种考虑晶内和晶间损伤起始和演化的统一损伤指示，并开发了一种内聚区模型-晶体塑性有限元法（CZM-CPFEM）方法、其中，采用具有耦合滑移和孪晶的晶体塑性以及基于应变能的损伤准则来揭示晶粒内部（GI）的塑性变形和损伤，同时选择二次名义应力（QUADS）和 CZM 的幂律来描述晶界（GB）的损伤和开裂。原位 SEM/EBSD 拉伸实验验证了细晶粒 (FG) 和细/超细晶粒 (F/UFG) TWIP 钢的应力-应变响应、孪生演变、损伤成核和开裂。结合微机械试验和 CZM-CPFEM 方法，研究和分析了晶粒大小、取向偏差角、晶粒取向和初始微空洞对 GI 和 GB 损伤和断裂的影响。结果表明，变形机制的相互作用促进了 GB 及其交界处微裂纹的优先萌生，而 GI 中的滑移带和孪晶束诱导了局部微裂纹的快速增长和扩展，最终导致晶间裂纹和晶内裂纹的混合断裂模式。此外，GB 损伤在 F/UFG TWIP 钢中占主导地位。增大晶粒尺寸可有效抑制 GB 损伤，增加 GI 损伤的比例。较大的错误取向角会削弱 GB 性能，而较小的错误取向角则能有效促进应变/应力协调，延迟 GI 和 GB 损伤。较大的滑移和孪生 Schmid 因子有利于激活位错和孪生，促进应变/应力协调以延缓微裂纹的产生，并改善均匀伸长率。此外，两种初始微空洞都能有效降低均匀拉伸强度（UTS）和断裂应变。具体来说，位于 GB 及其交界处的微空洞会增加 GB 损坏的百分比和晶间开裂的可能性，尤其是在 GB 的四重交界处。

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引用次数: 0