Abstract:The laser manufactured high-performance GH4169 Ni-based alloys were generally prepared in a closed environment, resulting in limited component dimension and increased fabrication cost. In order to broaden the application of laser additive manufacturing and remanufacturing GH4169 alloy, this work was attempted under different atmospheres (Ar, N2) in atmospheric environment. The results indicat that the laser-repaired layer under Ar atmosphere is mainly composed of γ phase and long-chain shaped Laves phase, with a typical columnar crystal structure. The tensile strength, yield strength and elongation is 874 MPa, 621 MPa and 23.1 %, respectively. In contrast, due to its higher thermal conductivity and faster molten pool cooling rate under N2 atmosphere, the laser-repaired layer is mainly composed of γ phase, granular Laves phase with smaller size and volume fraction, and granular (Ti,Nb)N phase. The dendritic structure is refined, with tensile strength, yield strength and elongation of 935 MPa, 649 MPa and 24.9 %, respectively. Under the combined effects of fine grain strengthening and second-phase precipitation strengthening, the laser repairing of GH4169 alloy can be achieved successfully under N2 atmosphere at low cost and high efficiency.