Mechanism Analysis of Carbide Formation in TZM Alloy

The formation and mechanism of carbide in powder metallurgy TZM molybdenum alloys during the sintering process were analyzed through the calculation of Gibbs free energy in the relative reactions of titanium carbide formation and the comparison of Mo phase diagrams. Results show that different from melt TZM, TiC is in situ produced by the route of Ti+C=TiC during the vacuum sintering process, and it is located at the phase boundaries of powder particles, the grain boundaries and the sub-grain boundaries. And a little TiC precipitates in the cooling process after sintering. Some Zr element exist in the form of simple substance while some forms the solid solution with Mo at high temperature, while precipitates the Laves phase Mo(2)Zr. ZrC is easily formed in the edge of Zr particles but hard in the grains.