Sintering process and particles migration mechanism of rapid sintering of W-Cu composites

In this article, the sintering process and particles migration mechanism of W-20wt%Cu composites sintered at 900°C for 660 s by thermal simulation instrument Gleeble-3500D were studied. The sintering process of the compacts was analyzed by dividing it into five stages and the sintering indexes at varied stages were calculated. Each sintering index corresponds to one particular kind of particles migration mechanism during a certain sintering stage. The results show that the sintering index is near infinitesimal in the first stage (0-10 s), and there will be relative slide and plastic deformation of particles. In the second stage (10-51 s), a sintering index of 1.24 is obtained, indicating plastic flow is the main mechanism of the particle migration. When it comes to the third stage (51-420 s), the index is found to be 2.34, implying the particle migration takes place by volume diffusion mechanism. The fourth stage (420-540 s) is with an index of 3.78 and surface diffusion is anticipated to be dominant in this stage. The last stage (540s-660 s) has an index of 2.92 and both volume diffusion and grain boundary diffusion prevail during this stage.