Synergistic effect of carbides and residual strain on the mechanical behavior of Ni-17Mo-7Cr superalloy made by wire-arc additive manufacturing

Abstract

Ni-17Mo-7Cr superalloy was successfully fabricated by Wire-arc additive manufacturing (WAAM) for the first time. Mechanical properties and microstructures were analyzed along the deposition direction of the WAAM alloy layer by layer. Both the hardness and tensile properties are stable, whereas a sharp decrease was observed in the superficial layers. The performance degradation can be ascribed to the less carbides and lower strain in the superficial layer. It is novel to find that the residual strain in superficial layer is the smallest and resulted in the non-uniform mechanical properties. Therefore, removing the superficial layer metal or heat treatment is suggested after WAAM processing.