A mixing microstructure containing Ni based amorphous structures was observed by TEM in the laser clad zones. As the uniformity of chemical composition and temperature is poor in the laser cladding, the amorphous stru...A mixing microstructure containing Ni based amorphous structures was observed by TEM in the laser clad zones. As the uniformity of chemical composition and temperature is poor in the laser cladding, the amorphous structure with some Ni 3Al crystals coexists in the cladding. The microhardness of the mixing amorphous structure is HV 600～800, which is lower than that of crystal phases in the coating. Differential thermal analysis (DTA) shows that Ni based amorphous structure exhibits a higher initial crystallizing temperature (about 588 ℃), which is slightly higher than that of the eutectic temperature of Al Si alloy. The wear test results indicate that there are some amorphous structures in the laser clad coating, which reduces the peeling of the granular phases from matrix, and improves the wear resistance.展开更多
文摘A mixing microstructure containing Ni based amorphous structures was observed by TEM in the laser clad zones. As the uniformity of chemical composition and temperature is poor in the laser cladding, the amorphous structure with some Ni 3Al crystals coexists in the cladding. The microhardness of the mixing amorphous structure is HV 600～800, which is lower than that of crystal phases in the coating. Differential thermal analysis (DTA) shows that Ni based amorphous structure exhibits a higher initial crystallizing temperature (about 588 ℃), which is slightly higher than that of the eutectic temperature of Al Si alloy. The wear test results indicate that there are some amorphous structures in the laser clad coating, which reduces the peeling of the granular phases from matrix, and improves the wear resistance.
