Shaohua Zhang
材料科学技术（英）
The orientation dependence of creep rupture lives of a single crystal superalloy at 760 oC/760 MPa was investigated. The orientations of the specimens tested were about 30o 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 a/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]- [¹111] 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..
关键词:
Single crystal superalloy
Shaohua Zhang
材料科学技术（英）
The stress rupture properties of a single crystal superalloy were tested at 975°C/255MPa as a function of the deviation degrees from [001]. The misorientation of the specimens away from [001] distributed approximately along a line between [001]-[011] and [001]-[-111] boundaries in the triangle of the stereographic projection. Creep rupture lifetimes of the specimens were not sensitive to the misorientation until the deviation degree exceeded ~30°. Two steps of lattice rotation were found in all specimens during creep, first towards the [001]-[-111] boundary, and then to [001] or [-111] along the boundary. Single slip and strong asymmetric deformation were observed during the first stage of lattice rotation in specimens with large misorientation. The rotation mechanism was associated with the activated slip systems according to the calculated Schmid factors. The impact of lattice rotation on the rupture properties was also discussed.
关键词:
Dislocation
