High Strength and High Wear-Resistant Ti Composites Fabricated by Powder Metallurgy Pressureless Sintering

In this work, high strength and high wear-resistant titanium matrix composites (TMCs) reinforced with in situ TiC derived from pyrolysis of polysilazane (PSZ) are fabricated successfully. The processing technology is developed with a novel powder metallurgy method combining solution-assisted wet mixing and pressureless sintering. The effects of PSZ addition on the microstructure, hardness, mechanical properties, and tribological properties are systematically studied. The TMCs possess better comprehensive properties compared to conventional ex situ methods. The pyrolysis of PSZ leads to the formation of TiC particles and N, Si atoms solid-solution in the Ti matrix. The microstructure of the composites is homogenous and fine-grained. The average grain size of alpha-Ti decreases significantly from 106.1 mu m of pure Ti to 37.2 mu m of the 1.5 wt% PSZ/Ti composite. Among these TMCs, the 1.5 wt% PSZ/Ti composite displays comprehensively excellent mechanical properties with the ultimate tensile strength (UTS) of 711 MPa, yield strength (YS) of 568 MPa, and elongation (EL) of 8.0%. In addition, the composite possesses a high wear resistance with a low specific wear rate of 0.355 x 10(-12) m(3) N-1 m(-1) under constant condition (0.03 m s(-1), 2N).

Automated summary

In this study, high strength and high wear-resistant titanium matrix composites reinforced with in situ TiC derived from pyrolysis of polysilazane were successfully fabricated. The effects of polysilazane addition on the microstructure, hardness, mechanical properties, and tribological properties were systematically studied. The composites exhibited better comprehensive properties compared to conventional methods, with a homogeneous and fine-grained microstructure, excellent mechanical properties, and high wear resistance.