Microstructure and thermal properties of mechanically alloyed W-1%TiC powder consolidated via two-step HIPping

In this work an influence of a fabrication route on the microstructure, thermal and mechanical properties of the W-1%TiC was studied. The W-1%TiC powder was mechanically alloyed using the stainless steel milling media. Two-step HIPping of the powder at 1300 °C (1573 K) and then at 1750 °C (2023 K) was performed. After second-step HIPping, in spite of 13.5% of porosity, bending stress and strain values were 300 MPa and 2%, respectively. On the contrary, the grain growth (from 0.7 up to 22.0 μm) and coarsening mechanisms of the TiC nanoparticles were observed. Up to 1200 °C (1473 K), thermal expansion parameters of two-step HIPped W-1%TiC alloy exhibited thermally unchanged values, comparable with a pure W rod, however, the thermal conductivity of the W-TiC alloy at RT was 26.5 W/m K, and at 1200 °C (1473 K) this parameter increased up to 44.8 W/m Km K.