Microstructural Investigation of TZM Alloys processed by Spark Plasma Sintering

Molybdenum based alloy having a nominal composition Mo-0.5Ti-0.1Zr-0.02C (wt%) popularly known as TZM alloy possess high temperature strength, high creep resistance, low coefficient of thermal expansion and high thermal conductivity. Processed TZM alloy contains TiC, ZrC and complex carbides which inhibit recrystallization at high temperatures and also improve the working conditions. In this study, the effect of sintering temperature, holding time and pressure on densification, microstructure and hardness of the spark plasma sintered TZM alloys were investigated. The sample sintered at 1575 °C for 150 second under 40 MPa exhibited the highest relative density, ∼98%. Microstructural characterization was performed by using FESEM and it was observed that TiC and ZrC dispersed through the microstructure. The average size of precipitates were measured as 7.5 and 3.5 m for TiC and ZrC, respectively.