Effect of strain rate on the mechanical properties of a tungsten particle reinforced titanium matrix composite
Yu Ren, Pengwan Chen, Li Zheng, Ziyue Zhang, Yanwei Lv, Chang Zhang
Abstract
Refractory metal particles can potentially be used to reinforce titanium matrix composites. In this research, a titanium matrix composite reinforced by 20 wt.% tungsten particles (20WP/Ti) was fabricated by powder metallurgy. The mechanical properties of 20WP/Ti were then evaluated over a broad strain rate range of 10−3–4 × 103 s−1. The microstructure of the composite consisted of W particle reinforcements, W diffusion regions, and an alloyed Ti matrix. The interdiffusion between W and Ti atoms produced broad diffusion regions and the Kirkendall effect. The W diffusion regions were a complex multiple-phase mixture of micron-sized β-Ti grains, nanoscale ω-Ti and α″-Ti phases and W nanoparticles. 20WP/Ti exhibited excellent mechanical properties due to the presence of multiple strengthening mechanisms including reinforcing phase strengthening, solid solution strengthening, and precipitation strengthening. The addition of W particle reinforcing phases suppressed the adiabatic shear sensitivity of the composite. When the strain rate exceeded 1400 s−1, the dynamic strength of 20WP/Ti declined upon increasing the strain rate, attributing to a mass of Kirkendall pores and the thermal softening effect of the β-Ti phase in the W diffusion region at high strain rates.