Chen Cen, Wang TzuChiang
State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing, 100190, China.
School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
Sci Rep. 2021 Apr 23;11(1):8859. doi: 10.1038/s41598-021-88333-1.
The strain rate and temperature effects on the deformation behavior of crystalline metal materials have always been a research hotspot. In this paper, a strain rate dependent thermo-elasto-plastic constitutive model was established to investigate the deformation behavior of crystalline metal materials. Firstly, the deformation gradient was re-decomposed into three parts: thermal part, elastic part and plastic part. Then, the thermal strain was introduced into the total strain and the thermo-elastic constitutive equation was established. For the plastic behavior, a new relation between stress and plastic strain was proposed to describe the strain rate and temperature effects on the flow stress and work-hardening. The stress-strain curves were calculated over wide ranges of strain rates (10-6000 s) and temperatures (233-730 K) for three kinds of crystalline metal materials with different crystal structure: oxygen free high conductivity copper for face centered cubic metals, Tantalum for body centered cubic metals and Ti-6Al-4V alloy for two phase crystal metals. The comparisons between the calculation and experimental results reveal that the present model describes the deformation behavior of crystalline metal materials well. Also, it is concise and efficient for the practical application.
应变速率和温度对晶体金属材料变形行为的影响一直是研究热点。本文建立了一个与应变速率相关的热弹塑性本构模型，以研究晶体金属材料的变形行为。首先，将变形梯度重新分解为三部分：热部分、弹性部分和塑性部分。然后，将热应变引入总应变中，建立了热弹性本构方程。对于塑性行为，提出了一种应力与塑性应变之间的新关系，以描述应变速率和温度对流动应力及加工硬化的影响。针对三种具有不同晶体结构的晶体金属材料，即面心立方金属的无氧高导电铜、体心立方金属的钽以及两相晶体金属的Ti-6Al-4V合金，在很宽的应变速率范围（10 - 6000 s⁻¹）和温度范围（233 - 730 K）内计算了应力 - 应变曲线。计算结果与实验结果的比较表明，本文模型能够很好地描述晶体金属材料的变形行为。此外，该模型在实际应用中简洁且高效。
