Orientation dependence of creep of Ni 3Al at intermediate temperature

Abstract

The orientation dependence of creep of single crystal Ni 3Al (1 at.% Ta) has been investigated at an intermediate temperature of 520°C and at a stress of 550 MPa. Steady-state creep was observed for all orientations. The higher the resolved shear stress on the cube cross-slip plane, the larger the steady-state creep rate. Surface slip line and TEM analysis confirmed that for most orientations the dislocations glide on the primary octahedral plane(s) during the primary stage but glide on the cube cross-slip plane(s) during the secondary stage. For the [ 11 ] orientation, however, the dislocations remain on the octahedral planes.