Unbalanced Sintering Process of WC-Co Alloy in Cemented Carbide Die

       Solid phase Because the mixture is difficult to achieve the desired uniformity, and the heating rate of the sintering process is relatively fast, the actual sintering process is an unbalanced sintering process. The situation is much more complicated.



      First of all, in the process of unbalanced sintering, before the temperature of the briquette reaches the eutectic temperature, the composition of the solid falling body does not meet the system's line, but lags behind the change of the a"a' line. At the same time, the sintered body is in eutectic The temperature is not kept warm. When the temperature is slightly higher than the eutectic temperature, the γ solid solution is not completely formed, and the composition of the Y solid solution does not reach the a'point, so it is impossible to completely exit into the liquid phase. Only when the temperature is continued to rise At this time, because tungsten carbide continues to dissolve into the liquid phase, the latter enters the liquid phase with different components (along the wc xc line) at different temperatures. At the same time, WC also continues to dissolve into the liquid phase. At the temperature Reach sintering



      At county level (1400C), the composition of the liquid phase is not point c, but a point on the be line. At the same time, there are a large number of V solids with a content of tungsten carbide less than a point. If it is kept at the sintering temperature (usually), the carbonization will continue at the same time, and the solid solution and the liquid phase will dissolve so that all the components of the y solid solution are gradually reached. Point and street. When the linear change reaches 6 o'clock, it enters the liquid phase, and the composition of the surface liquid phase controls the pressure change.