Evaluation of Press-and-Sinter Processing Parameters in Titanium Hydride Powder Metallurgy

The use of hydrogenated titanium powders combined with traditional PM techniques may lead to a significant reduction in the manufacturing costs of titanium components. In this work, the advantages and limitations of the use of TiH2 powder consolidated through the conventional press-and-sinter method were investigated. Processing parameters related to the compaction and sintering were studied for a TiH2 powder in the particle sizes <355 μm, <150 μm and <45 μm. Optimized compaction conditions were achieved by using admixed lubricant and compaction pressure of 800 MPa. The mechanisms involved in the compaction of powders were detailed through the fit of compressibility data to a theoretical model originally developed for titanium powders. Densification of samples was favored by the reduction in particle size and increase in sintering temperature up to 1300 °C. The positive effects of hydrogen release during dehydrogenation were verified through the results of sintered densities and the reduction of oxygen levels. Limitations were observed mainly regarding the flowability of powders and the difficulty to achieve full densification.