In-situ synthesis and superhigh modulus of network structured TiC/Ti composites based on diamond-Ti system

In order to enhance the elastic modulus and strength of titanium, novel continuous network structured TiC particle reinforced Ti (TiC/Ti) composites were successfully fabricated by hot pressing sintering based on diamond-Ti system. The results showed that 5 vol% fine diamond powders can be homogeneously adhered onto the surface of large Ti powders by lower energy ball milling process of 250 rpm/5 h/3:1. The mixed powders resulted in equiaxed network microstructure of TiC/Ti composites formed by continuous TiC particle reinforcement around large Ti powders after in-situ reaction between diamond and Ti. However, high energy ball milling process of 300 rpm/10 h/10:1 must be employed due to excessive diamond powders, which can result in TiC/Ti composites with a novel flattened network microstructure. Among the composites, the one introduced by 10 vol% diamond exhibited the highest elastic modulus of 184 GPa, which was increased by 64% compared with pure Ti (112 GPa). The composites with 5 vol% and 7.5 vol% diamond presented 830 MPa and 1480 MPa compressive yield strengths respectively, which were 1.9- and 3.4-fold that of pure Ti (429 MPa). The superior elastic modulus and strength of the composites was mainly attributed to the continuous TiC network microstructure and remained reinforcement-lean region based on the Hashin-Shtrikman theory. (C) 2020 Elsevier B.V. All rights reserved.