No abstract

The characterization of tilt and twist low angle grain boundaries (LAGBs) has been performed, and the influences of LAGBs on intermediate-temperature creep deformation behavior have been investigated in a single crystal Ni-based superalloy. It is found that the tilt boundary is composed of intrinsic edge dislocations, and the twist boundary mainly consists of intrinsic screw dislocations. LAGB type is found to have a significant influence on the rupture life of SX superalloy deformed at 760 ºC. The tilt boundary shows a much better creep resistance compared to that of a twist boundary. The dislocation configuration near the grain boundary indicates that most of the mobile dislocations can pass through the tilt boundary, but they are basically inhibited and piled-up at the twist boundary during creep deformation.