放电等离子烧结TA15钛合金及石墨烯增强TA15复合材料微观组织与力学性能

Titanium alloys and titanium-based composites are widely used in the field of aerospace owing to their advantages such as low density and high specific strength. Graphene has been found to significantly improve the mechanical properties of metal matrix composites at a lower content due to high modulus, fracture strength, and specific surface area. To achieve excellent mechanical properties, TA15 titanium alloy was fabricated via spark plasma sintering (SPS), and the effects of sintering temperature, sintering time, and sintering pressure on the densification, microstructure, and mechanical properties of the obtained alloys were investigated. The results indicate that the sintering parameters exert trivial effect on the phase composition of the sintered TA15 titanium alloy. The microstructure of the sintered alloy is mainly determined by the sintering temperature, and the prolonged sintering time will cause microstructure coarsening. Meanwhile, the sintering pressure does not have obvious effect on the sintered microstructure. Furthermore, higher sintering temperature, longer sintering time, and accurate increase in sintering pressure contribute to the densification process of TA15 titanium alloy. At room and high temperatures, the comprehensive mechanical properties exhibited by the sintered TA15 titanium alloy are determined by density and microstructure. The dense TA15 titanium alloy can be fabricated via SPS under the sintering conditions of 900^oC, 50 MPa, and 5 min. Such alloy exhibits optimally comprehensive mechanical properties at room and high temperatures. Additionally, 0.5% (mass fraction) graphene reinforced TA15 composites were fabricated by SPS under the sintering conditions of 900^oC, 50 MPa, and 7 min. When compared with TA15 titanium alloy, the compression yield strength and ultimate compressive strength of composites have significantly improved at room and high temperatures.