Abstract: Microstructure changes of laser remelted Ni-based alloy hot sprayed-welding layers after different aging treatment are studied by means of optical microscope(OM), scanning electron microscopy(SEM) and X-ray diffraction(XRD), and microhardness is also compared. The results show that, after laser remelting, microstructure of hot sprayed-welding layers has been significantly refined and improved, the remelted layers mainly consist of fine dendrites with small lamellar eutectic structure in their branches. When aging temperature is kept constant(600 ℃), with the extention of aging time, the morphology of dendrites remain original, but the eutectic structures nodulize and lose their lamellar structure. And at the same time, a lot of hard phase precipitate in the matrix, which enable matrix a high hardness; When aging time is kept constant(6 h), with the increasing of aging temperature, the morphology of dendrites become equiaxial apparently, meanwhile, precipitated carbide grow up together and its type has also changed, which led to a decline of layer hardness; When aging temperature exceed 800 ℃, the hardness of remelted layer fall sharply.

Key words: Aging treatment, Hot sprayed-welding layers, Laser remelting, Microstructure, Property