Creep Behavior of Single Crystal Superalloy DD6 at 760°C and 980°C

Abstract

The tensile creep properties of the second generation single crystal superalloy DD6 with [001], [011] and [111] orientations were investigated under different stress levels at 760°C and 980°C, and the creep mechanism of DD6 alloy was discussed. The results show that DD6 alloy possesses good creep properties, and obviously exhibits anisotropic behavior. The deviation degree between stress axis and [001] crystallizing orientation gradually deceases, while deviation degree between stress axis and [011], [111] crystallizing orientations increases due to lattice rotation during creep. The alloy with [001] orientation provides geometry hardening tendency, but the alloy with [011] and [111] orientations supplies geometry softening tendency. The creep deformation of DD6 alloy with three orientations mainly concentrates on the matrix channels and y' phase is stable at 760°C. The alloy demonstrates complicated creep behavior and the creep deformation with three orientations is situated at both matrix channels and y' phases at 980°C, and the directional coarsening of γ' phase occurs.