Orientation Dependence of Stress Rupture Properties of a Ni-based Single Crystal Superalloy at 760 °C

The orientation dependence of creep rupture lives of a single crystal superalloy at 760 °C/760 MPa was investigated. The orientations of the specimens tested were about 30° away from [001]. The results showed that specimens with orientations on the [001]-[011] boundary had the longest rupture life. The deformation of these specimen were controlled by α/2<110> slip and a few stacking faults with two orientations were observed. On the other hand, specimens with orientations near the [001]-[011] boundary or on the [001]-[11] boundary showed short rupture lives, and stacking faults with single orientation were observed in these specimens. The rupture properties and the deformation mechanisms were discussed based on the dislocation pattern and the calculated Schmid factors for different specimens.