Microstructure and wear behaviour of laser-cladded gamma-Ni-ss/Mo2Ni3Si coating

摘要

A series of gamma -Ni-ss/Mo2Ni3Si composite coatings were deposited on the hot-rolled 0.45 wt-% C steel plate using DJ-HL-T5000B CO2 laser system. The microstructure and phase constitution were studied by XRD and SEM with an attached EDS. Microhardness, toughness and dry sliding wear behaviour of the alloy coating were studied. Research results show that all the designed coatings with different compositions are composed of gamma -Ni-ss and Mo2Ni3Si. The volume fraction of Mo2Ni3Si, as well as the average microhardness, shows an increased tendency as the Ni content decreases from 65% to 50%. The addition of gamma -Ni-ss ductile phase can effectively improve the toughness of Mo2Ni3Si-based alloy and prevent the spread of the cracks. Furthermore, the wear resistance of laser-cladded gamma -Ni-ss/Mo2Ni3Si coatings exhibits a distinct improvement compared with that of the substrate. The wear mass loss and wear mechanism are affected by the volume fraction of Mo2Ni3Si.