Abstract
In order to evaluate quantitatively the strain dependence of the activation volume of iron containing of 0.01 mass % C at very high strain rates, strain rate reduction tests are performed at strains of about 0.09,0.17,0.22,0.26,0.32,0.39 and 0.44, respectively at the strain rate of about 10000/sec. The reduction ratio caused by the collision between an impact bar and a decelerator is 0.586 of the strain rate before reduction. The activation volume is determined from the amount of the flow stress drop obtained from the reduction tests. The results indicate that the activation volume decreases slightly with strain.
