中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 10 No. 1 February 2000 |
（1. Department of Materials Science and Engineering,
Donghua University, Shanghai200051, P.R.China;
2. State Key Laboratoryfor Mechanical Behavior of Metallic Materials,
Xi′an Jiaotong University, Xi′an 710048, P.R.China;
3. Northwestern Nonferrous Metals Manufacturer, Baoji721000, P.R.China）
Abstract:Dynamic tension tests were employed to investigate the effect of strain rate on mechanical behaviors of Ti10V2Fe3Al and 30CrMnSiNi2A. The strain rate ranges from 10-4to 103s-1. Experimental results showed that the yield strength (σs), ultimate strength(σu) and elongation(δ5) increase, but strain hardening exponent(n) decreases with the rise of strain rate(.ε) by refractive lines. The reasons thatσsandσuincrease with increasing.εare concerned with thermal activation. The high strain rate induced increasing plasticity is associated with adiabatic heating of specimen, impact twinning and suppression of strain-induced-phase transformation. Strain hardening exponentncan be considered a con-
stant under quasi-static loading, but decreases rapidly till an ideal plastic state(n=0) after strain rate surpassing a critical value(102s-1). The mechanism ofndecreasing with the increase of.εis related to the increase ofσsand suppression of strain-induced-phase transformation.
Key words: dynamic tension tests; strength; plasticity; strain-hardening
