粉末冶金 TC4-B₄C 原位反应制备 TiC+TiB 增强 TC4 基复合材料的显微组织和力学性能

In this paper, Using TC4 and B₄C powders as raw materials, TC4 matrix composites reinforced with different contents of TiB and TiC were prepared by spark plasma sintering (SPS). The sintered samples ware hot extruded. The effects of different contents of TiB and TiC on the microstructure and mechanical properties of TMCs and their high temperature mechanical properties were studied in situ reaction system of TC4-B₄C. The results show that the in-situ TiC and TiB are firmly bonded with the matrix, TiC is like spherical particles, and TiB is like whisker. The reinforced phase in the matrix presents an obvious trend of three-dimensional network distribution along the boundary of primary particles. Compared with the unreinforced TC4 alloy, the matrix grain of the composite is significantly refined and there are high density dislocations, and the room temperature and high temperature properties of the titanium matrix composites are significantly improved. When the content of B₄C is 0.5% at room temperature, the matrix has good connectivity and exhibits high strength (1246 MPa) and good elongation (12.7%). When the B₄C content is 1.64% at 400 ℃, the tensile strength and elongation are 1112 MPa and 6.9%, respectively.