(1. 中南大学 数学科学与计算技术学院，长沙 410083；
2. 北京科技大学 材料科学与工程学院，北京 100083)
摘 要: 基于高速压制成形的工艺原理，对金属粉体成形过程中的高应变率、粘性效应和硬化速率先上升后下降的变形特性进行分析。将非线性弹簧、线性弹簧和高应变率Maxwell单元并联构成复合非线性粘弹滞体，并用来描述压制过程中金属粉体的高应变率和粘性效应特征；将非线性弹簧的形变指数视为应变的函数，用形变指数在压制过程中的变化来描述金属粉体硬化速率先上升后下降的变形特征，构建金属粉体高速压制成形的本构关系。分别用线性、二次和三次函数来近似形变指数，分析相应的应力—应变曲线。结果表明：所构建的本构方程能描述金属粉体高速压制成形的变形特性。
关键字: 高速压制成形；高应变率；加工硬化；应力—应变曲线
metal powers during high velocity compaction process
（1. School of Mathematical Science and Computing Technology, Central South University, Changsha 410083, China;
2. School of Materials Science and Engineering, University of Science and Technology Beijing,
Beijing 100083, China）
Abstract:Based on the mechanism of high velocity compaction, the deformation characteristics of metal powder during the forming process were analyzed, which include high strain rate, viscous effect and first increasing then decreasing characteristics of hardening velocity. The non-linear spring, linear spring and high strain rate Maxwell element were combined to form a composite nonlinear viscoelastic body, which was used to describe the high strain rate and viscous effect of metal powders. The deformation index of the term of nonlinear spring was viewed as a function with respect to strain, and the change of deformation index was used to describe the first increasing then decreasing characteristics of hardening velocity of powder in high velocity compaction. The constitutive relation of metal powder in high velocity compaction was established. The deformation function was approximated to deformation index by linear, quadratic and cubic polynomial and the corresponding stress—strain curves were analyzed respectively. The results indicate that the deformation characteristics of metal powder in high velocity compaction can be described by the constitutive equation.
Key words: high velocity compaction; high strain rate; work hardening; stress—train curve
