Rate-related high-temperature deformation of nickel-based single-crystal superalloys

The strain rate dependency is a key parameter to determine the behavior of nickel-based single-crystal super-alloys, in particular at elevated temperatures. To further address the underlying physical mechanism, we conceived and designed the present study, focusing on the strain-rate-controlled high-temperature deformation mode. Our results show that the alloy demonstrates pronounced work hardening upon tension at 900 degrees C when the strain rate is 0.1 s(-1), whereas strain softening is observed if the rate is reduced to 0.001 s(-1). Such a deviation stems from the thermal diffusion and elemental segregation, which changes the stacking fault energy and defect configuration. The present study is therefore expected to enrich the current understanding of strain-rate-dependent high-temperature deformation behavior and to guide the design of high-performance nickel-based single-crystal superalloy.