High temperature creep in copper single crystals oriented for easy glide Part II. Creep kinetics

A high initial creep strain rate is characteristic for creep in copper sing le crystal oriented for easy glide. The creep strain rate decreases in time rather quickly, but the steady state is not attained even at very large cr eep strains, if ever. In the present work, approximate values of the appare nt activation energy Q(c) and the apparent stress exponent n are obtained f rom the lowest creep strain rates measured at any given temperature and the applied stress. From the macroscopic deformation of the oblong cross secti on specimen, the relative contribution of submicroscopic slip in two slip s ystems is estimated; these slip systems are associated with the highest val ues of the shear stress. It is found that the contribution of the submicros copic slip associated with the main slip system may not be the most signifi cant one.