Cavitation erosion characteristics of TiC reinforced metal matrix composite layer fabricated by plasma cladding

摘要

The present study focused on fabricating a novel metal matrix composite (MMC) layer with a good cavitation erosion resistance by plasma cladding of TiC/Ni60 powders on the matrix of austenitic stainless steel 1Cr18Ni9Ti. After the cladding process, the microstructures and the resistance to cavitation erosion of the MMC layer were investigated in comparison with the ZG06Cr13Ni5Mo martensite stainless steel. The MMC layer consisted of y-Ni dendrite, interdendritic eutectic (γ-Ni austenite, M_(23)C_6, M_7C_3 and CrB) and TiC particles. With such hard carbides and borides, the MMC layer possessed a high microhardness (860 HVO-2), almost three times that of the matrix material ZG06Cr13Ni5Mo (260 HVO-2). The weight loss of the reference material ZG06Cr13Ni5Mo was greater than that of the MMC layer during the cavitation erosion process because of its lower microhardness. The microstructural observation indicated that the cavitation corrosion of the MMC layer initiated from the interface of y-Ni matrix and TiC particles due to the weak bonding of these two phases. However, the cavitation erosion of ZG06Cr13Ni5Mo initiated from the lath interfaces of martensites and the grain boundaries.