Influence Of Small Degree Deviation From [001] Orientation On Creep Behavior Of Ni-Based Single Crystal Superalloys

The creep behavior of Ni-based single crystal superalloys with small degree deviation from [001] orientation is strongly influenced by temperature, gamma' phase size and the level of applied stress. This research presented a review on effects of small orientation deviation on creep behavior of single crystal superalloys. The variations in the creep properties of alloys with small degree deviation from [001] orientation originate from different deformation mechanisms. Besides, these mechanisms correspond to different threshold stresses which are associated with the occurrence of primary creep and creep rate. At intermediate temperatures (760 similar to 850 degrees C), the creep behavior of single crystal alloys is highly sensitive to small misorientation but relatively insensitive above 850 degrees C. The size of y phase is inferred to exert influence on the creep behavior of alloys with orientation deviation at intermediate temperatures. However, at elevated temperatures, the rafting process can be accelerated by higher thermal activation, and thus the mechanical properties become less relevant to the size of gamma' precipitates.