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

摘要

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-Mc-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.