Creep Anisotropy in Single-Crystal Superalloy DD6 near the [001] Orientation

Abstract

This paper has studied the anisotropy in the creep properties of DD6 alloy under different temperatures and applied stresses. The results reveal that the anisotropic creep of DD6 alloy near the [001] orientation is strongly influenced by the temperature in the range of 650–980 °C. The anisotropy in the primary creep strain and rupture lifetime at an intermediate temperature of 760 °C is dependent on the applied stress. Compared with the specimens oriented close to the [001]–[111] boundary, the specimens oriented close to the [001] direction and the [001]–[011] boundary exhibit lower primary creep strains and longer rupture lifetimes at intermediate temperatures and high applied stresses. With the increase in the testing temperature or the decrease in the applied stress, the anisotropic creep behavior of the alloy near the [001] orientation disappears. The mechanism of anisotropic creep is attributed to heterogeneous γ′ precipitate deformation by <112> {111} slip.