However, the plastic flow becomes stable gradually, as the strain rate increases, owing to activation of twinning deformation to release the concentration of stress at grains boundaries.

• 随着应变速率的提高， 由于孪生变形机制的激活， 大晶粒产生孪生变形， 使晶界处的应力集中得到缓解，塑性流变过程逐渐稳定。