(1. 天津理工大學(xué) 機(jī)械工程學(xué)院，天津 300191；
2. Department of Electrical and Materials Science, Faculty of Engineering Sciences,
Kyushu University, Kasuga, Fukuoka 816-8580, Japan)
摘 要: 采用高應(yīng)變分辨率的螺旋彈簧蠕變試驗(yàn)法，研究晶粒尺寸dg為40 μm純銅在低溫(T <Tm，Tm為純銅的熔點(diǎn))和應(yīng)變速率小于1×10-10 s-1條件下的蠕變和粘彈性回復(fù)行為。采用基于蠕變曲線尺度因子的數(shù)據(jù)解析法，代替?zhèn)鹘y(tǒng)基于外推的穩(wěn)態(tài)蠕變速率的蠕變數(shù)據(jù)解析法。結(jié)果表明:純銅低溫、低應(yīng)力初始蠕變行為可由冪律蠕變方程描述，因?yàn)閮缏扇渥兎匠坛跏紖?shù)不隨蠕變時(shí)間改變而變化；粘彈性應(yīng)變?yōu)閺椥詰?yīng)變的1/6；粘彈性應(yīng)變速率的對數(shù)和粘彈性應(yīng)變的對數(shù)呈線性關(guān)系(斜率為1)。因此，純銅低溫、低應(yīng)力蠕變可能由三維位錯(cuò)網(wǎng)的收縮機(jī)制控制。
關(guān)鍵字: 純銅；蠕變；位錯(cuò)；粘彈性；蠕變本構(gòu)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
