The effect of creep strain on grain boundary sliding during diffusion creep

Abstract

A now theoretical approach is used to determinc the contribution that grain boundary sliding makes to the overall creep strain during diffusion creep. The approach has the advantages that it is generally applicable to three dimensional grain shapes and that the effect of creep strain can be treated exactly. Furthermore, since the basic approach is to determine the sliding and diffusional displacements on individual grain boundaries those can do used to predict parameters connected with the crept microstructure. The approach is applied to the creep of initially equiaxed grains and shows that grain boundary sliding makes a decreasing contribution to the overall creep strain with increasing creep strain. Further parameters connected with the microstructure and which are experimentally verifiable are predicted. Finally, data aro presented on the sliding and diffusional displacements between grains in terms of the boundary orientation in order to give a graphical representation of, the boundary displacements and their variation with creep strain.