Microstructure and properties of Y_2O_3-doped steel-cemented WC prepared by microwave sintering

摘要

Steel-cemented WC was prepared by ball milling,cold compacting and microwave sintering with Fe powder as the matrix,WC as the hard phase and the addition of rare earth Y2O3.The results show that the interface of the WC particles and Fe matrix exhibits excellent wettability and liquidity when the microwave sintering temperature reaches 1,280°C.The density and mechanical properties of the steel bonded WC carbides could be greatly improved,the hard phases become finer and more uniform dispersed owing to the addition of Y2O3.With the increase of the Y2O3contents,the grain becomes uniform and fine first,and then gathers and grows up.The relative density,microhardness and bending strength all rise first,reaching the maximum values of 97.29%,HV1024 and 1,267.60 MPa at 0.5%Y2O3,respectively,and then decrease.Moreover,the relative density and mechanical properties of the steel-cemented WC with nano-Y2O3are higher than that with micron-Y2O3,which indicates that the effect of nano-Y2O3is better than that of the micron-Y2O3.