GRAIN-BOUNDARY DESIGN AND CONTROL FOR HIGH-TEMPERATURE MATERIALS

Recent experimental work has been reviewed concerning the effects of grain boundary structure on grain boundary sliding and migration, and other boundary phenomena involved in high temperature plasticity. A basic knowledge of the structure-dependent intergranular phenomena is important for a full understanding of the heterogeneity and characteristic features of high temperature deformation and fracture, because the structural effects of grain boundaries enhance the boundary-induced heterogeneity of deformation and fracture in polycrystals. The grain boundary character distribution (GBCD) has been shown to be important and useful in explaining and controlling high temperature plasticity, superplasticity and fragility in polycrystals. The potential use of grain boundary design and control for high temperature materials has been discussed on the basis of recent work concerning GBCD, texture and other microstructural factors. The recent achievement of grain boundary design and control for high temperature materials has been briefly introduced.