Study on Creep Anisotropy at 760°C of a Single Crystal Superalloy

Abstract

In this paper, the creep properties of a second generation single crystal superalloy DD412 with [001], [011] and [111] orientation at 760°C were studied. The experimental results show that the creep properties of DD412 alloy with different orientations have significant anisotropy under the stress of 580MPa-620MPa at 760°C. The [001] and [111] oriented alloys have remarkably better creep performance than [011] oriented alloy. And the creep performance of [111] oriented alloy is superior to that of [001] oriented alloy under the condition of 760°C/620MPa, while the tendency is inverse under the condition of 760°C/580MPa. The dislocation configurations of the alloy with different orientations during creep process are significantly different, resulting in creep anisotropy. For [001] and [111] oriented alloy, there are large number of dislocations in the γ channel that intersect and form local high-density dislocation aggregation, which has a strong blocking effect on the movement of dislocations. For [011] oriented alloy, the <110>{111} dislocations intersect each other to form <112>{111} partial dislocations and stacking faults, cutting into the γ′ phase, which lead to rapid growth of creep deformation and the poor creep performance of [011] oriented alloy.