Microstructural Characteristics of Ti-Based Composites with Various Ceramic Reinforcements Manufactured via Hydrogen-Assisted Blended Elemental Powder Metallurgy

The manufacturing of in situ reinforced titanium matrix composites by the sintering of titanium hydride and ceramic powder blends is an attractive and cost-efficient process. Herein, a novel two-stage (double-compaction/double-sintering) hydrogen-assisted powder approach is suggested to produce uniform highly dense Ti-based composites reinforced with TiB, TiC, and dual TiC + TiB phase particles. In this approach, the hydrogenation and milling of presintered products enable the initial porous materials to transform into hydrogenated prealloyed (PA) powders of controlled sizes, and a second press-and-sinter process further converts the PA powders into nearly dense composite microstructures with evenly distributed fine reinforcements. The adverse effect of the raw reinforcing powder size on microstructure uniformity, porosity, and mechanical characteristics of the presintered in situ composites becomes negligible in final sintering stage. The reduction of the porosity and enhancement of the hardness indicate that the hydrogen-assisted double-compaction and double-sintering blended elemental powder metallurgy (BEPM) + PA approach enables the low-cost fabrication of Ti-based composites with suitable mechanical characteristics.