Microstructure and Mechanical Properties of Ti-TiH 2 Based Matrix Composites Reinforced with xTiB 2 Particles Processed by Powder Metallurgy.

The structure changes, microstructure evolution, and mechanical properties during Powder Metallurgy (PM) through High Vacuum Sintering of a Ti-TiH₂ matrix reinforced with Titanium Diboride (TiB₂) particles were investigated. Composites were fabricated at 850, 1100, and 1300 °C. The strategy for the fabrication process was to use the PM route employing titanium hydride (TiH₂) to reduce the consumption of Commercially Pure Titanium (CP-Ti). The structure of the composites was analyzed using X-Ray Diffraction (XRD), while Optical Microscopy (OM), and Field-Emission Scanning Electron Microscopy (FE-SEM) analysis were used to study the microstructure. Vickers microhardness and nanoindentation were performed to evaluate the elastoplastic and mechanical properties. According to the results, the unreinforced Ti-TiH₂ sample presented higher sinter-ability, attaining relative density values of 93% with the higher sintering temperature. Composite samples showed TiB and TiB₂ phases without the presence of any TiH₂ residual phase. The highest mechanical properties were measured for reinforced samples with 30 vol.% of TiB₂, sintered at 1300 °C, showing values of 509.29 HV and 4.94 GPa for microindentation Vickers and nanoindentation essays, respectively, which resulted in 8.5% higher than the values for the unreinforced sample. In addition, their H/Er and H³/Er² ratios are higher than those of CP-Ti suggesting a better wear resistance of the Ti-TiH₂ matrix-reinforced samples, combined with its mechanical properties makes it more suitable than CP-Ti for its potential in biomedical applications. [ABSTRACT FROM AUTHOR]