Some Effects of Particle Size on the Sintering of Titanium and a Master Sintering Curve Model

The press-and-sinter method of producing net shapes was applied to titanium alloys. The quantitative effects of the particle size of titanium and Ti-6Al-4V powders on the green and sintered densities were examined. Most powders were pressed at 100 to 800 MPa and sintered under vacuum at 1100 A degrees C, 1200 A degrees C, or 1300 A degrees C for 2 hours. The green density was higher for coarser powders and for powders with a wider size distribution. The sintered density was higher for finer powders and for powders with a wider size distribution. The densification parameter was little affected by the compaction pressure but increased as the particle size was reduced. An empirical model of densification based on the master sintering curve approach was developed, with the activation energy for densification of titanium found to be approximately 160 kJ/mol.