Abstract
The applicability of the dip test to the measurement of the mean internal stress during deformation was examined. It is found that the method is valid only when the dislocation velocity is proportional to the effective stress or when the internal stress is nearly 100% of the flow stress. An extrapolation method is proposed to minimize the error of the dip test. By applying this method to the high-temperature deformation of high-purity aluminium and Al-5.7 at%Mg and from above theoretical prediction, it is found that the internal stress is the main component of the flow stress in pure aluminium, while the frictional stress contribution is as large as that of the internal stress in the Al–Mg alloy.
