论文标题

基于第一原理计算的单晶镍的预测晶体可塑性建模

Predictive Crystal Plasticity Modeling of Single Crystal Nickel Based on First-Principles Calculations

论文作者

Shimanek, John D., Qin, Shipin, Shang, Shun-Li, Liu, Zi-Kui, Beese, Allison M.

论文摘要

为了减少对晶体可塑性有限元方法(CPFEM)中实验拟合数据的依赖,提出了一种方法,该方法基于密度功能理论(DFT)整合了第一原理计算,以预测纯Ni单晶的应变硬化行为。使用基于DFT的方法计算出的理想剪切强度和弹性特性,通过PEIERLS-NABARRO方程来评估流动阻力,其硬性行为通过在第一原则计算中对超级细胞施加菌株进行建模。单独考虑的是,纯边缘位错的弹性相互作用捕获了单滑系统上小菌株的硬性行为。对于较大的菌株,通过边缘和螺钉流电阻组件的应变加权线性组合捕获硬化。在当前框架中没有预测组合速率,而是通过大量载荷方向与实验一致的结合速率(〜0.4),这可能通过融合中尺度物理学的分析模型来证明一种可能进行更具预测性的晶体可塑性建模的途径。

To reduce reliance on experimental fitting data within the crystal plasticity finite element method (CPFEM), an approached is proposed that integrates first-principles calculations based on density functional theory (DFT) to predict the strain hardening behavior of pure Ni single crystals. Flow resistance was evaluated through the Peierls-Nabarro equation using the ideal shear strength and elastic properties calculated by DFT-based methods, with hardening behavior modeled by imposing strains on supercells in first-principles calculations. Considered alone, elastic interactions of pure edge dislocations capture hardening behavior for small strains on single slip systems. For larger strains, hardening is captured through a strain-weighted linear combination of edge and screw flow resistance components. The rate of combination is not predicted in the present framework, but agreement with experiments through large strains (~0.4) for multiple loading orientations demonstrates a possible route for more predictive crystal plasticity modeling through incorporation of analytical models of mesoscale physics.

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