Effect of Microstructure and Deformation on Hardness Distribution of Wrought Precipitation Strengthened Ni-Based Alloy after Creep Damage

Abstract

To establish the creep life assessment method for wrought precipitation strengthened Ni-based alloys, the factors which influence the hardness after creep damage were studied. Hardness measurements and microstructure quantification were done for crept specimen of γ’-Ni₃Al precipitation strengthened alloy, TOS1X-2. Hardness increased with EBSD KAM and GAM value of measured location, suggesting the hardening by creep induced strains. Grain boundary and twin boundary were found to suppress the plastic deformation by hardness indent. Grains oriented <001> to the stress axis showed high hardness, while grains oriented <101> showed relatively low. This indicated the possible existence of orientation dependence of strain hardening, which might be explained by the number of slip systems likely to operate and the interactions of dislocation movement. The hardness seemed to be influenced by the γ’ phase precipitation strengthening, plastic deformation resistance by grain boundary and strain hardening for each grain orientations.