(1. 天津理工大学 机械工程学院，天津 300191；
2. Department of Electrical and Materials Science, Faculty of Engineering Sciences,
Kyushu University, Kasuga, Fukuoka 816-8580, Japan)
摘 要: 采用高应变分辨率的螺旋弹簧蠕变试验法，研究晶粒尺寸dg为40 μm纯铜在低温(T <Tm，Tm为纯铜的熔点)和应变速率小于1×10-10 s-1条件下的蠕变和粘弹性回复行为。采用基于蠕变曲线尺度因子的数据解析法，代替传统基于外推的稳态蠕变速率的蠕变数据解析法。结果表明:纯铜低温、低应力初始蠕变行为可由幂律蠕变方程描述，因为幂律蠕变方程初始参数不随蠕变时间改变而变化；粘弹性应变为弹性应变的1/6；粘弹性应变速率的对数和粘弹性应变的对数呈线性关系(斜率为1)。因此，纯铜低温、低应力蠕变可能由三维位错网的收缩机制控制。
关键字: 纯铜；蠕变；位错；粘弹性；蠕变本构方程
（1. School of Mechanical Engineering, Tianjin University of Technology, Tianjin 300191, China;
2. Department of Electrical and Materials Science, Faculty of Engineering Sciences,
Kyushu University, Kasuga, Fukuoka 816-8580, Japan）
Abstract:Creep and anelastic backflow behaviors of pure copper (4N Cu) with grain size dg=40 μm were investigated at low temperatures of T <0.3Tm (Tm is melting point) and ultra-low creep rates of ≤1×10-10 s-1 by a high strain-resolution measurement (the helicoid spring specimen technique). Analysis of creep data was based on the scaling factors of creep curves instead of the conventional extrapolated steady-state creep rate. Power-law creep equation is suggested to be the best for describing the primary transient creep behavior, because the pre-parameter does not apparently change with elapsed time. The observed anelastic strains are 1/6 of the calculated elastic strains, and linear viscous behavior was identified from the logarithm plot of the anelastic strain rate versus anelastic strain (slope equals 1). Therefore, the creep anelasticity is suggested to be due to the unbowing of there-dimensional network of dislocations.
Key words: pure copper; creep; dislocation; anelasticity; constitutive creep equation
