Coarse-grained superplasticity of a Ni-Co-based superalloy

A near-superplastic tensile elongation of up to 232% at 1140 degrees C and 0.001 s � 1 for a coarse-grained Ni-Co-base superalloy with an average grain size of 85 mu m is reported. Nevertheless, poor grain deformation coordination and low grain boundary bonding strength led to terrible thermoplasticity for the coarse-grained alloy below 1100 degrees C. Dynamic recrystallization (DRX) relieved the stress concentration and decreased the damage accumulation during superplasticity, improving the ductility with the increase in temperature within the gamma + gamma ' dualphase regime.

Automated summary

A coarse-grained alloy with an average grain size of 85 μm exhibited near-superplastic tensile elongation at high temperature and strain rate. Dynamic recrystallization process alleviated stress concentration and damage accumulation, thereby improving the ductility of the material.