Modeling high-temperature creep of anisotropic material

Abstract

Cast single-crystal superalloys are being used as turbine blades in modern aeroengines with [001] axis oriented along the direction of principal stress. This allows use of higher operating temperature with associated improvement in efficiency. Although [001] is the natural direction of crystal growth in these alloys it is often not possible to attain perfect alignment. Consequently, besides time-dependent deformation this would induce a change in cross-sectional shape and crystal orientation of the blade as a result of service exposure. Therefore in order to exploit their full potential it is necessary to develop a predictive system which could model effect of crystallographic anisotropy on high-temperature creep deformation of such materials. The paper reviews the recent developments in this direction and suggests that modelling not only helps in identifying the dominant mechanisms of deformation but also suggests simple experiments to verify them.