Microstructures and mechanical properties of TiC-particulate-reinforced Ti–Mo–Al intermetallic matrix composites

Abstract

The microstructures and mechanical properties of titanium carbide (TiC)-particulate-reinforced B2-structured Ti–Mo–Al intermetallic matrix composites (Ti–Mo–Al–TiC composites) with various matrix compositions and TiC contents have been systematically investigated. All the Ti–Mo–Al–TiC composites were composed of a B2-ordered Ti–Mo–Al matrix and off-stoichiometric TiC particles. Fine globular and rod-like TiC particles preferentially formed in the interdendritic regions of the matrix. Primary TiC in relatively large particle sizes and a uniform particle distribution were observed in the composites containing 10 at.% TiC. The compression strength was found to depend on both the matrix composition and TiC content. The contribution of TiC particles to the overall strength of the composites at high temperatures (≥800 °C) was not as strong as that at room temperature. Compared with the unreinforced Ti–Mo–Al matrix materials, the Ti–Mo–Al–TiC composites exhibited improved high-temperature deformability. The composites deformed above 800 °C showed the plastic deformation of TiC particles. The strengthening mechanisms involved in the Ti–Mo–Al–TiC composites are discussed by correlating the microstructural features with the strengths of the composites. The impressive mechanical properties of the Ti–Mo–Al–TiC composites endow them with great potentials in high-temperature structural applications.