等径通道挤压铝在较宽温度和应变率下的单轴压缩行为(英文)

Uniaxial compressive behavior of equal channel angular pressing Al at wide temperature and strain rate range

在较宽温度和应变率范围内,对等径通道挤压(ECAP)方法制备的超细晶铝进行单轴压缩试验,研究温度对流动应力、应变硬化率和应变率敏感性的影响。结果表明:ECAP铝与粗晶粒度铝相比,温度对其流动应力和应变率敏感性的影响更大,超细晶铝的温度敏感性较粗晶粒度铝弱。根据试验结果,估计了不同温度和应变率下的表观激活体积。ECAP铝在准静态应变率下,与林位错相互作用是主导的热激活机制,而粘曳在高应变率下起着更重要的作用。

Uniaxial compressive experiments of ultrafine-grained Al fabricated by equal channel angular pressing(ECAP) method were performed at wide temperature and strain rate range. The influence of temperature on flow stress, strain hardening rate and strain rate sensitivity was investigated experimentally. The results show that both the effect of temperature on flow stress and its strain rate sensitivity of ECAPed Al is much larger than those of the coarse-grained Al. The temperature sensitivity of ultrafine-grained Al is comparatively weaker than that of the coarse-grained Al. Based on the experimental results, the apparent activation volume was estimated at different temperatures and strain rates. The forest dislocation interactions is the dominant thermally activated mechanism for ECAPed Al compressed at quasi-static strain rates, while the viscous drag plays an important role at high strain rates.