Compressive deformation behavior of a near-beta titanium alloy

Highlights: → The hardness of the adiabatic shear bands was significantly lower than the bulk microstructure. → The hardness of the β and α'' phases were not dependent on strain rate and loading type. → The flow stress were similar in both the low and high strain rate tests due to the martensitic phase. → The fracture surface dimple size changed with testing strain rate. -- Abstract: This paper documents an investigation into the compressive deformation behavior of a solution treated near β titanium alloy. The mechanical testing was carried out at strain rates of 10-3 S-1 and 103 S-1 by a numerically controlled hydraulic MTS machine and a Split Hopkinson Pressure Bar test system, respectively. The results show that the work hardening characteristics of the titanium alloy were not significantly influenced by strain rate. Further, the flow stress followed a similar trend in both the low and high strain rate tests because of the formation of a martensitic α'' phase. The flow stress at high strain rate (103 S-1) was slightly lower than that in the quasi-static condition (10-3 S-1). The hardness in the β phase was higher than that in the martensitic α'' phase. Also, the lowest hardness was located in the adiabatic shear bands (ASBs) which were associated with high strain rate deformation. Electron Backscatter Diffraction (EBSD) mapping confirmed the presence of the α'' phase in deformed specimens at both strain rates. The fracture characteristics were observed using scanning electron microscopy (SEM).