Microstructure and mechanical properties of particle reinforced high-temperature titanium composites

In this research, a novel high-temperature titanium alloy, Ti750, was used as matrix and SiCp, SiCw, B4C, and GNPs as reinforcements to prepare both ex situ and in situ composites using spark plasma sintering process. The microstructure and mechanical properties of the samples were then examined and evaluated. The results show that the microstructures and phase compositions of the ex situ composites contain mainly SiC particles homogeneously distributed in the alpha-Ti matrix. The in situ synthesized composite, however, mainly contains TiC and Ti5Si3 reinforced phases in the Ti-rich matrix. The in situ composite had the best mechanical properties among all the materials. It recorded 1164 HV and 924 MPa in Vickers microhardness and room temperature compressive tests respectively. It also had the lowest apparent porosity (4.89%) among the composites but slightly higher than matrix material (4.67%). The in situ composite thus presents a better option to the Ti750 alloy which is currently used for high-temperature applications.