Creep deformation and damage characteristics of nickel-based superalloy GH4169

To further understand the creep behavior of nickel-based superalloys, creep deformation and damage characteristics of nickel-based superalloy GH4169 were investigated systematically by using SEM, EBSD and TEM characterizations in this study. Creep tests were conducted at 650 °C under 820 MPa.The results indicated that the fractions of low-, high-angle, and twin grain boundaries changed significantly after creep. Due to the grain rotation mechanism, the overall microstructure changed from random to preferred crystallographic orientation. //loading direction (LD) oriented grains were rotated to //LD and //LD fibers, resulting in the decrease of fiber, and the increase of and fibers. Cases of oriented grains rotating into and orientations were also provided. Deformation twin and stacking faults were determined as the main deformation mechanisms. The failure of the specimen was induced by intergranular brittle fracture. The grain boundaries with special characteristics, namely high Schmid factor m and low Schmid factor mismatch Δm of neighbouring grains, and low geometric compatibility factor m’, exhibited high susceptibility to cracking. •The grain boundaries with special characteristics exhibit high susceptibility to cracking, depending on local orientation.• //loading direction (LD) oriented grains are rotated to //LD and //LD fibers during creep.•The main texture components are Rotated Brass and Copper, and lack of Rotated Copper and Rotated Goss.•Deformation twin and stacking faults are determined as the main deformation mechanisms.