IN100 Ni-based superalloy fabricated by micro-laser aided additive manufacturing: Correlation of the microstructure and fracture mechanism

IN100 Ni-based superalloy fabricated by micro-laser aided additive manufacturing (micro-LAAM) was investigated in this study. After solution treatment and aging (STA) of the micro-LAAMed IN100 alloy, hierarchical γ′ phases were recognized and characterized, which contributed significantly to the high ultimate tensile strength (~1050 MPa) and acceptable ductility (5%) at 25 °C and 600 °C. The tensile fractured surfaces of the as-built and STAed IN100 were characterized by dimples and dimples/cleavages, respectively. The high cycle vibration fatigue (HCVF) behavior was preliminarily studied through simulating the service conditions of some cantilever structures in automobile and aerospace industries. Compared with the cast IN100, the micro-LAAMed IN100 superalloys (as-built or STAed) both exhibited inferior HCVF lives. The HCVF behavior was discussed and correlated with the microstructure characteristics, such as the preferred growth direction of the grains in micro-LAAMed IN100 and the massive interfaces existing in the final obtained material. In the present study, the hierarchical γ′ phases were beneficial to the static tensile property, whereas detrimental to the HCVF behavior of the final obtained IN100 to some extent.