International Journal of Plasticity最新文献_第10页

Role of thermal stress-driven dislocation and low-angle grain boundary migration in surface plastic deformation and grain orientation evolution of tungsten under thermal shock 热应力驱动的位错和低角度晶界迁移在热冲击下钨表面塑性变形和晶粒取向演化中的作用

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-01-01 DOI: 10.1016/j.ijplas.2024.104205

Meng-Chong Ren , Yu-Fei Nie , Han-Qing Wang , Yue Yuan , Fan Feng , You-Yun Lian , Hao Yin , Long Cheng , Duo-Qi Shi , Guang-Hong Lu

This study reveals that thermal fatigue loading (transient thermal shock), similar to that in fusion environments, can serve as a surface processing technique for BCC metals. Regions with a {110} grain orientation can be selectively achieved in varying sizes and locations on the sample surface. Furthermore, our experiments confirm that the specific localized orientation transformation obtained through this method exhibits certain high-temperature stability at 1573 K (above the recrystallization temperature of tungsten). The experiment employed a 0.25 GW/m² high-energy pulsed electron beam for 1 ms to cyclically load the tungsten surface, simulating edge localized mode events in fusion conditions. It was found that tungsten exhibited significant surface grain orientation transformation (distinct {110} grain orientation) under low strain (∼ 1 %) after transient thermal shocks, a phenomenon rarely mentioned in studies of thermal shock on fusion reactor divertor materials. Microstructure characterization results suggest that this localized orientation transformation, induced by minor surface damage, primarily results from the generation, movement, and evolution of dislocations into subgrain and low-angle grain boundaries. The cyclic accumulation of the migration of kink-like subgrain/low-angle grain boundaries under transient thermal stress at high temperatures drives this process. Subsequently, crystal plasticity finite element method simulations based on dislocation slip were conducted to study the surface grain orientation transformation of tungsten under compressive thermal stress. This predictive capability provides valuable guidance for understanding the service conditions of fusion reactor divertor materials. Furthermore, we propose that cyclic transient thermal shocks can serve as an effective surface processing technique for metals, enabling the formation of specific localized grain orientations.

本研究表明，热疲劳加载（瞬态热冲击），类似于熔合环境，可以作为BCC金属的表面加工技术。具有{110}晶粒取向的区域可以选择性地在样品表面的不同尺寸和位置上实现。此外，我们的实验证实，通过该方法获得的特定局部取向转变在1573 K（高于钨的再结晶温度）时具有一定的高温稳定性。实验采用0.25 GW/m²高能脉冲电子束循环加载钨表面，模拟聚变条件下的边缘局域模式事件。发现钨在瞬态热冲击后的低应变（~ 1%）下表现出明显的表面晶粒取向转变（明显的{110}晶粒取向），这一现象在聚变反应堆转向器材料的热冲击研究中很少提及。微观结构表征结果表明，这种由轻微表面损伤引起的局部取向转变主要是由位错在亚晶界和低角度晶界的产生、移动和演化引起的。高温瞬态热应力作用下扭结状亚晶/低角度晶界迁移的循环积累驱动了这一过程。随后，采用基于位错滑移的晶体塑性有限元模拟方法，研究了压缩热应力作用下钨的表面晶粒取向转变。这种预测能力为理解聚变反应堆导流器材料的使用状况提供了有价值的指导。此外，我们提出循环瞬态热冲击可以作为一种有效的金属表面加工技术，使特定局部晶粒取向的形成成为可能。

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引用次数: 0

The interfacial damage of the deformation heterogeneity in the transformation-induced plasticity (TRIP)-assisted duplex stainless steel 相变诱导塑性（TRIP）辅助双相不锈钢中变形不均匀的界面损伤

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-01-01 DOI: 10.1016/j.ijplas.2024.104209

Wenbin Zhang , Miao Jin , Shuo Hao , Mingshuai Huo , Zhenyi Huang , Lei Chen , Wenzhen Xia

The characteristic of differences in material properties between phases gives rise to significant deformation heterogeneity in dual-phase or multi-phase materials, consequently resulting in complex damage laws. In this study, the microcracks characteristics of transformation-induced plasticity (TRIP)-assisted duplex stainless steel were observed after large deformation (engineering strain up to 55%). It has been determined that microcracks invariably occur at interface locations, including the phase boundary between original austenite and ferrite, the grain boundary of original austenite, and the grain boundary of ferrite. The deformation heterogeneity of various types of interfaces is analyzed by using crystal plasticity finite element method (CPFEM). Deformation degree coordination parameter

k_{l}

and slip transfer parameter

k_{t f}

are established, based on the velocity gradient tensor

L_{p}

and the slipping rate

\dot{γ}

of activated slip system in CPFEM, to analyze the multi-slip heterogeneous deformation behavior of grains on both sides of the interface. A novel interfacial damage model considering the slip transfer parameter

k_{t f}

is established, which reveals the correlation between deformation heterogeneity and damage mechanism, to provide a criterion for various types of interfacial failure behaviors. The interfacial damage model based on deformation heterogeneity can stand as an invaluable instrument for exploring the damage behaviors of two-phase or multi-phase materials.

双相或多相材料的相变特性差异导致其变形不均匀性显著，损伤规律复杂。在本研究中，观察了变形诱导塑性（TRIP）辅助双相不锈钢在大变形（工程应变高达55%）后的微裂纹特征。结果表明，微裂纹总是发生在界面位置，包括原奥氏体与铁素体的相界、原奥氏体的晶界和铁素体的晶界。采用晶体塑性有限元法分析了不同类型界面的变形不均匀性。基于CPFEM中激活滑移体系的速度梯度张量Lp和滑移率γ˙，建立变形度协调参数kl和滑移传递参数ktf，分析界面两侧晶粒的多滑移非均质变形行为。建立了考虑滑移传递参数ktf的界面损伤模型，揭示了变形非均质性与损伤机理之间的关系，为各种类型的界面破坏行为提供了准则。基于变形非均质性的界面损伤模型是研究两相或多相材料损伤行为的重要工具。

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引用次数: 0

Tensorial interaction model for the effect of short-range order on single crystalline medium entropy alloys 单晶介质熵合金短程有序影响的张量相互作用模型

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-01-01 DOI: 10.1016/j.ijplas.2024.104200

Cewen Xiao , Long Yu , Xiazi Xiao

In order to help comprehend the influence of short-range order (SRO) structures on both the mechanical property and microstructural evolution of single crystalline medium entropy alloys (MEAs), a physical mechanism-based crystal plasticity theory is developed in this work, which covers the deformation mechanisms of dislocation-SRO interaction, network dislocation interaction, dislocation-twin boundary interaction, twinning deformation and solid solute strengthening. Thereinto, a tensorial interaction model is proposed to effectively characterize the spatial interaction between SROs on the characteristic planes and dislocations on the slip planes, which can not only address the increase of yield stress related to the impediment of slip dislocations by SROs, but also capture the phenomenon of decreasing flow stress after the yield point due to the destruction of SRO structures. Moreover, twinning deformation has been additionally taken into account by considering the complex hardening behavior related to both co-planar and non-co-planar twinning. To help validate the proposed constitutive equations, the stress-strain relations of single crystalline CrCoNi under three different loading directions are compared between the experimental data and theoretical results. A good agreement is achieved that can help verify the proposed theoretical model and facilitate the comprehension of the underlying deformation mechanisms.

为了更好地理解短程有序结构（SRO）对单晶介质熵合金（MEAs）力学性能和微观组织演变的影响，本文建立了基于物理机制的晶体塑性理论，包括位错-SRO相互作用、网络位错相互作用、位错-孪晶界相互作用、孪晶界变形和固体溶质强化的变形机制。其中，提出了一种张拉相互作用模型，有效表征特征面上的SRO与滑移面上的位错之间的空间相互作用，既能解决SRO阻碍滑移位错导致屈服应力增加的问题，又能捕捉到SRO结构破坏导致屈服点后流动应力下降的现象。此外，通过考虑与共面和非共面孪晶相关的复杂硬化行为，还考虑了孪晶变形。为了验证本文提出的本构方程，比较了三种不同加载方向下单晶CrCoNi的应力-应变关系。得到的结果很好地吻合，这有助于验证所提出的理论模型，并有助于理解潜在的变形机制。

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引用次数: 0

Interactions of austenite-martensite interfaces with Ni4Ti3 precipitates in NiTi shape memory alloy: A molecular dynamics investigation NiTi形状记忆合金中Ni4Ti3相与奥氏体-马氏体界面相互作用的分子动力学研究

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-01-01 DOI: 10.1016/j.ijplas.2024.104203

Gabriel Plummer , Mikhail I. Mendelev , Othmane Benafan , John W. Lawson

Precipitation of secondary phases is a common strategy used to control both the structural and functional properties of shape memory alloys. It can be used to promote nucleation of the martensitic transformation as well as improve cyclic stability. Less is understood about how precipitates affect the progression of an ongoing transformation, i.e., motion of austenite-martensite interfaces. In this study, we performed molecular dynamics simulations of the interaction of austenite-martensite interfaces moving in the NiTi alloy with Ni₄Ti₃ precipitates. It was found that the nanoscale precipitates obstruct interface motion until a sufficient undercooling is reached. The simulation results can be quantitatively explained with thermoelastic effects – elastic deformation of the precipitates acts to oppose the thermodynamic driving force favoring the transformation. A simple model is proposed to predict a more difficult transformation in shape memory alloys with higher concentrations of and/or harder precipitates. Additionally, simulations of cyclic transformations implicate inelastic deformation at the precipitate-matrix interface as one mechanism responsible for the cyclic drift in transformation characteristics. Deformation originated in a thin, amorphous interfacial layer and expanded with increasing cycles.

二次相的析出是控制形状记忆合金结构和功能性能的常用方法。它能促进马氏体相变的成核，提高循环稳定性。对于沉淀如何影响正在进行的转变的进展，即奥氏体-马氏体界面的运动，人们知之甚少。在本研究中，我们对Ni4Ti3析出物与NiTi合金中移动的奥氏体-马氏体界面的相互作用进行了分子动力学模拟。研究发现，纳米级的析出物阻碍了界面的运动，直到达到足够的过冷。模拟结果可以用热弹性效应来定量解释——析出相的弹性变形与有利于转变的热力学驱动力相反。提出了一个简单的模型来预测具有较高浓度和/或较硬沉淀的形状记忆合金的更困难的转变。此外，循环转变的模拟表明，沉淀-基体界面的非弹性变形是导致转变特征循环漂移的一种机制。变形起源于薄的非晶界面层，并随着循环次数的增加而扩大。

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引用次数: 0

Stability of high energy superlattice faults in Ni-based superalloys from atomistic simulations ni基高温合金中高能超晶格缺陷的原子模拟稳定性

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-01-01 DOI: 10.1016/j.ijplas.2024.104199

Valery V. Borovikov , Mikhail I. Mendelev , Timothy M. Smith , John W. Lawson

High energy stacking faults generated by lattice dislocations entering the strengthening precipitates of Ni-based superalloys are responsible for the unique mechanical properties of these structural materials. However, the question about stability of these faults has not received the attention it deserves. Using atomistic simulations, we show that the anti-phase boundary (APB) can spontaneously transform into super intrinsic stacking fault (SISF) and the complex stacking fault (CSF) can spontaneously transform into L1₂ lattice structure. The former transformation explains the experimentally observed presence of isolated SISFs and super extrinsic stacking faults (SESFs) in the precipitates. Finally, multiple studies were focused on finding alloying additions which increase the APB and CSF energies. We demonstrate therefore that alloying additions which increase stacking fault energies may conversely decrease their stabilities.

晶格位错进入镍基高温合金强化相产生的高能层错是导致这些结构材料具有独特力学性能的原因。然而，这些断层的稳定性问题并没有得到应有的重视。通过原子模拟，我们发现反相边界（APB）可以自发地转化为超本禀层错（SISF），复杂层错（CSF）可以自发地转化为L12晶格结构。前者的转变解释了在实验中观察到的析出相中存在孤立的sifs和超外在层错（sesf）。最后，多项研究的重点是发现合金添加物可以增加APB和CSF能量。因此，我们证明了合金的添加会增加层错能，反过来会降低层错的稳定性。

引用次数: 0

Controlling behaviour of constitutive models for rocks using energy dissipations 基于能量耗散的岩石本构模型控制行为

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-01-01 DOI: 10.1016/j.ijplas.2024.104196

Nhan T. Nguyen , Giang D. Nguyen , Murat Karakus , Ha H. Bui , Dat G. Phan

The behaviour of rocks and other similar geomaterials is governed by different underling dissipative mechanisms that can be represented by damage and plastic strains in continuum constitutive modelling. The explicit links between these dissipative mechanisms and constitutive behaviour are established in this study in a generic thermodynamics-based framework. The key feature of this proposed framework and derived damage-plasticity models is the capability to control the constitutive behaviour through varying the contributions of different dissipative mechanisms to the total dissipation budget. Particularly, three fractions of the total dissipation budget related to damage, plastic volumetric and shear dissipations are introduced to control the constitutive behaviour through the evolution of damage variable and plastic strains, respectively. The examples provided show the performance and promising features of the proposed framework.

岩石和其他类似岩土材料的行为是由不同的底层耗散机制所控制的，这些耗散机制可以用连续本构模型中的损伤和塑性应变来表示。这些耗散机制和本构行为之间的明确联系在本研究中建立在一个通用的基于热力学的框架。该框架及其衍生的损伤塑性模型的关键特征是能够通过改变不同耗散机制对总耗散预算的贡献来控制本构行为。特别地，引入了与损伤、塑性体积和剪切耗散相关的总耗散预算的三个部分，分别通过损伤变量和塑性应变的演变来控制本构行为。所提供的示例显示了所提出框架的性能和有前途的特点。

引用次数: 0

Mechanistic insights into twinning and detwinning during fatigue short crack growth in zirconium alloys 锆合金疲劳短裂纹扩展过程中孪晶和去孪晶的机理研究

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-01-01 DOI: 10.1016/j.ijplas.2024.104210

Weifeng Wan , Yu Cheng , Chaitanya Paramatmuni , Xiaoxian Zhang , Vasilis Karamitros , Dawei Huang , Xiaojun Yan

This study investigates fatigue short crack growth in Zircaloy-4 alloy, revealing phenomena of twinning and detwinning of {

10 \bar{1} 2

}<

10 \bar{1} 1

> tensile type at the vicinity of the crack. Twinning primarily occurs at the crack tip, crack deflection sites, and adjacent heterogeneities such as grain boundaries and triple junctions. Both twinning and slip contribute simultaneously to crack tip plasticity. The occurrence of twinning significantly increases the average stress and stored energy density at the crack tip, thereby accelerating short crack propagation. Twinning forms earlier in Z-type samples (with the texture pole aligned with the Z-direction) compared to Y-type samples, resulting in an earlier and more pronounced increase in crack growth rate. Detwinning is observed exclusively in Z-type samples, induced by substantial changes in stress distribution at the crack tip, likely due to dislocation pile-up at the twin boundary during crack growth.

本文研究了锆合金的疲劳短裂纹扩展，揭示了{101¯2}<；101¯1>；裂纹附近的拉伸型。孪晶主要发生在裂纹尖端、裂纹偏转部位和相邻的异质处，如晶界和三联结。孪晶和滑移同时影响裂纹尖端的塑性。孪晶的出现显著提高了裂纹尖端的平均应力和存储能量密度，从而加速了短裂纹的扩展。与y型样品相比，z型样品（织构极与z方向一致）的孪晶形成得更早，导致裂纹扩展速率的增加更早，也更明显。只在z型试样中观察到去孪晶，这是由裂纹尖端应力分布的实质性变化引起的，可能是由于裂纹扩展过程中孪晶边界处的位错堆积。

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引用次数: 0

Enhanced strength-ductility synergy in medium entropy alloy via phase selective precipitation 通过相选择析出增强中熵合金的强度-塑性协同效应

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-01-01 DOI: 10.1016/j.ijplas.2024.104204

Weijin Cai , Qiang Long , Shenghan Lu , Kang Wang , Junyang He , Shiteng Zhao , Zhiping Xiong , Jun Hu , Wenzhen Xia , Ian Baker , Kefu Gan , Min Song , Zhangwei Wang

Precipitation strengthening is paramount in the development of high-performance medium/high entropy alloys (M/HEAs). In this work, we showcase a phase-selective precipitation design applied to a (Ni_67.2V_32.8)₉₀Ti₅Al₅ MEA to enable enhanced strength-ductility synergy. Upon annealing at 950 °C, multiple precipitates form in this MEA, including L2₁, σ and hexagonal close packed (HCP) phases. However, an increase of 50 °C in annealing temperature removes most of the aforementioned precipitates except for the L2₁ phase. Density functional theory calculations are conducted to elucidate the formation mechanisms of phase-selective precipitation. Such selective approach to precipitation induces a brittle to ductile transition, increasing tensile elongation from 4 % to 43 % in our MEAs. Remarkably, the ultimate tensile strength of 1000 °C annealing MEA is maintained at ∼1.4 GPa, surpassing that of the precipitation-free Ni_67.2V_32.8 base alloy (∼1.1 GPa), but with a comparable tensile elongation. Analytical models suggest that the increase in strength is attributed to both precipitation strengthening and grain refinement strengthening due to the pinning effect of precipitates. In particular, we investigate the complex deformation response of the L2₁ phase, which includes the formation of slip steps and a phase transformation from body-centered cubic (BCC) to body-centered tetragonal (BCT) structures, with the underlying mechanisms revealed through experimental characterization and molecular dynamics simulations. This co-deformation of matrix and L2₁ precipitates alleviates stress concentration at phase boundaries during straining and further maintains the microband-induced plasticity in the matrix till later deformation stage. All these result in the excellent strain hardening and thus, markedly enhancing ductility. Our findings pave new ways to craft strong and ductile M/HEAs by selecting hard-yet-deformable intermetallic precipitates.

析出强化是高性能中/高熵合金（M/HEAs）发展的关键。在这项工作中，我们展示了一种应用于（Ni67.2V32.8）90Ti5Al5 MEA的相位选择沉淀设计，以实现增强的强度-延性协同。950℃退火后，该MEA中形成多种析出相，包括L21相、σ相和六方密堆积相（HCP）。然而，退火温度提高50°C，除L21相外，上述析出相大部分去除。通过密度泛函理论计算，阐明了相选择沉淀的形成机理。这种选择性沉淀方法诱导脆性到韧性的转变，在我们的mea中将拉伸伸长率从4%提高到43%。值得注意的是，1000°C退火MEA的极限抗拉强度保持在~ 1.4 GPa，超过无析出的Ni67.2V32.8基合金（~ 1.1 GPa），但拉伸伸长率相当。分析模型表明，强度的增加既归因于析出相的强化，也归因于析出相的钉住作用导致的晶粒细化强化。特别地，我们研究了L21相的复杂变形响应，包括滑移步骤的形成和从体心立方（BCC）到体心四方（BCT）结构的相变，并通过实验表征和分子动力学模拟揭示了潜在的机制。基体与L21析出相的共变形缓解了应变过程中相界处的应力集中，进一步保持了基体的微带诱导塑性直至变形后期。所有这些都导致了优异的应变硬化，从而显著提高了塑性。我们的发现通过选择坚硬但可变形的金属间析出物，为制造强韧性的M/HEAs铺平了新的道路。

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引用次数: 0

Training of a physics-based thermo-viscoplasticity model on big data for polypropylene 基于物理的聚丙烯热粘塑性模型的大数据训练

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-01-01 DOI: 10.1016/j.ijplas.2024.104179

Benoit Jordan, Dirk Mohr

Research on data-driven constitutive models has demonstrated their outstanding ability to provide highly accurate predictions of the general stress-strain response after learning from data only. Here, we demonstrate that physics-based models can equally benefit from training procedures relying on big data. Specifically, we employ the thermo-mechanically coupled viscoplasticity model [Anand, L., Ames, N.M., Srivastava, V., Chester, S., 2009. A thermo-mechanically coupled theory for large deformations of amorphous polymers. Part 1: Formulation. International Journal of Plasticity] to describe the large deformation response of polypropylene. It combines both mechanism-based evolution equations and high mathematical flexibility. More than 100 constant velocity and strain rate jump experiments are performed on flat tensile specimens extracted from 3 mm thick isotactic polypropylene sheets. The exact cross-sectional area is measured with surround DIC, while an IR camera monitored the surface temperature field. The experiments typically reached true strains greater than 0.8 and cover temperatures and strain rates ranging from 25 to 85 °C and 10^–4 to 10⁰ s^-1, respectively. Training over 100,000 unique random combinations of experiments is performed to identify all model parameters. The effect of the training (and testing) subsets size and composition is carefully analyzed to ensure a high generalization ability. It is found that training based on 26 randomly-selected experiments leads to the most robust parameter estimates. The obtained model performs remarkably well on all our experiments (among which 70 % are unseen during training) with a root mean square error of less than 1.5 MPa. As a byproduct, we also found that there exists a subset of two specific experiments for training that lead to an equally accurate model for polypropylene.

对数据驱动构成模型的研究表明，这些模型具有出色的能力，只需从数据中学习，就能对一般应力-应变响应做出高度准确的预测。在这里，我们证明了基于物理学的模型同样可以从依靠大数据的训练程序中获益。具体来说，我们采用了热机械耦合粘弹性模型[Anand, L., Ames, N.M., Srivastava, V., Chester, S., 2009.无定形聚合物大变形的热机械耦合理论。第 1 部分：公式。国际塑性学报》]描述了聚丙烯的大变形响应。它结合了基于机理的演化方程和高度的数学灵活性。在从 3 毫米厚的同素异形聚丙烯片材中提取的平面拉伸试样上进行了 100 多次恒速和应变速率跃变实验。使用环绕 DIC 测量精确的横截面积，同时使用红外摄像机监测表面温度场。实验的真实应变通常大于 0.8，温度和应变率范围分别为 25 至 85°C 和 10-4 至 100 s-1。对 100,000 个独特的随机实验组合进行训练，以确定所有模型参数。对训练（和测试）子集的大小和组成的影响进行了仔细分析，以确保较高的泛化能力。结果发现，基于 26 个随机选择的实验进行训练，可以获得最稳健的参数估计。所获得的模型在所有实验（其中 70% 在训练过程中未见）中表现出色，均方根误差小于 1.5 兆帕。作为副产品，我们还发现存在两个特定的实验子集，这两个子集的训练可为聚丙烯建立一个同样精确的模型。

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引用次数: 0

Multiscale computational analysis of crack initiation at the grain boundaries in hydrogen-charged bi-crystalline alpha-iron 充氢双晶α-铁晶界裂纹萌发的多尺度计算分析

IF 9.4 1区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Plasticity

Pub Date : 2025-01-01 DOI: 10.1016/j.ijplas.2024.104182

Yipeng Peng , Thanh Phan , Haibo Zhai , Liming Xiong , Xiang Zhang

This paper presents a mesoscale concurrent atomistic–continuum (CAC) simulation of crack initiation at the atomically structured grain boundaries (GBs) in bi-crystalline BCC iron (

α

-Fe) charged with hydrogen (H). By retaining the atomistic GB structure evolution together with the long-range dislocation-mediated plastic flow away from the GB in one model at a fraction of the cost of full molecular dynamics (MD), CAC enables us to probe the interplay between the atomic-level H diffusion, the nanoscale GB cavitation, crack initiation, growth, as well as the dislocation activities far away from the GB. Our several main findings are: (i) a tensile strain normal to the GB plane largely promotes the H diffusion towards the GB. (ii) the plasticity-induced clustering of H atoms (PICH) is identified as an intermediate process in between the H-enhanced localized plasticity (HELP) and H-enhanced de-cohesion (HEDE). (iii) PICH significantly amplifies the local stress concentration at the GB and decreases its cohesive strengths, and (iv) the GBs with different atomic structures fail differently. In detail, the H-charged

Σ 3

GB fails through micro-twinning assisted void nucleation and coalescence, while the H-charged

Σ 9

GB fails through crack initiation and growth accompanied by dislocation emission. Compared with nanoscale molecular dynamics (MD) simulations, the mesoscale CAC models get one step closer to the experimentally measurable length scales and thus predict reasonably lower GB cohesive strengths. This research addresses one key aspect of how H impacts the GB cohesive strengths in

α

-Fe. It offers insights into the multiscale processes of hydrogen embrittlement (HE). Our findings highlight the importance of using concurrent multiscale models, such as a combination of CAC, crystal plasticity finite element (CPFE), and cohesive zone finite element method (CZFEM), to understand HE. This will, in turn, support the development of new strategies for mitigating HE in a variety of engineering infrastructures.

本文介绍了一种中尺度原子-连续并行（CAC）模拟，用于模拟带氢（H）的双晶 BCC 铁（α-Fe）原子结构晶界（GB）处的裂纹起始。通过在一个模型中保留原子级晶界结构演化以及长程位错介导的远离晶界的塑性流动，CAC 使我们能够探究原子级氢扩散、纳米级晶界空化、裂纹萌发、生长以及远离晶界的位错活动之间的相互作用。我们的几个主要发现是(i) 与 GB 平面垂直的拉伸应变在很大程度上促进了 H 向 GB 的扩散；(ii) 塑性诱导的 H 原子团聚（PICH）被认为是介于 H 增强局部塑性（HELP）和 H 增强去凝聚（HEDE）之间的中间过程。(iii) PICH 显著放大了 GB 的局部应力集中并降低了其内聚强度，以及 (iv) 具有不同原子结构的 GB 会以不同方式失效。具体而言，带 H 电荷的 Σ3 GB 通过微孪晶辅助空洞成核和凝聚而失效，而带 H 电荷的 Σ9 GB 则通过裂纹引发和增长并伴随位错发射而失效。与纳米级分子动力学（MD）模拟相比，中尺度 CAC 模型更接近于实验测量的长度尺度，因此预测的 GB 内聚强度更低。这项研究解决了 H 如何影响 α-Fe 中 GB 内聚强度的一个关键问题。它为氢脆（HE）的多尺度过程提供了见解。我们的研究结果突显了使用并行多尺度模型（如 CAC、晶体塑性有限元 (CPFE) 和内聚区有限元法 (CZFEM) 的组合）来理解氢脆的重要性。这反过来将有助于开发新的战略，以减轻各种工程基础设施中的高能耗。

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引用次数: 0