Reactive sintering mechanism of Ti + Mo_2C and Ti + VC powder compacts

摘要

TiC reinforced Ti-matrix composites have been synthesized successfully by reactive sintering of Ti-1.5%Fe-2.25%Mo (wt%) powder compacts with addition of Mo_2C and VC particles. The reactions for the formation of TiC particles start at 600 °C, but the distribution of TiC particles and the densification behavior in the two compacts are significantly influenced by the metal carbides (Mo_2C or VC). The compact with addition of Mo _2C has a relative density of 98% after sintering at 1300 °C for 1.5 h, but TiC particles are agglomerated in the Ti matrix. The compact with addition of VC has a relative density of about 91% after sintering at 1300 °C for 1.5 h, but TiC particles distribute more homogenously in the Ti matrix. Different TiC particle distribution and densification behaviors are attributed to the reaction rates between Ti and metal carbides and the subsequent diffusion process.