超细晶工业纯钛的变形、应变速率敏感性和激活体积

Deformation, strain rate sensitivity and activation volume of ultrafine-grained commercially pure Ti

摘要:

在温度为250~450 ℃、应变速率为1×10-4-1 s-1的条件下，对超细晶工业纯钛进行变速率压缩实验，计算超细晶工业纯钛的应变速率敏感性因子和激活体积，并研究超细晶工业纯钛的变形行为。研究结果表明：超细晶工业纯钛在稳态变形阶段存在流变软化效应，这是受变形过程中大角度晶界和位错活动所控制的。超细晶工业纯钛的应变速率敏感性因子和激活体积在数值上都相对较低，应变速率敏感性随着变形温度的升高而增加，但激活体积独立于变形温度。应变速率敏感性和激活体积的数值表明晶粒内部位错之间的交互作用几乎不发生，而位错与晶界之间的交互作用显著影响超细晶工业纯钛的塑性变形。

Abstract:

The deformation behavior of ultrafine-grained (UFG) commercially pure (CP) Ti was investigated. The strain rate sensitivity and activation volume were calculated from strain rate jump tests performed at a temperature range of 250-450 °C and strain rate of 1×10-4 - 1 s-1. The results show that flow softening effect in steady state of deformation occurs in UFG CP Ti which is controlled by high-angle grain boundaries and dislocation activity during the deformation process. Strain rate sensitivity of UFG CP Ti is relatively low in value and increases with the rise of temperature. The activation volume of UFG CP Ti is also low in value and invariant with temperature. The values of strain rate sensitivity and activation volume indicate that dislocation-dislocation interactions within the grain interiors take place scarcely and interactions between dislocation and grain boundary can significantly affect plastic deformation of UFG CP Ti.