Hot deformation behavior of commercial pure vanadium

Abstract

The hot deformation behavior of pure vanadium was studied by uniaxial compression tests carried out in vacuum to a true strain of 0.6 in the temperature range of 800 to 1400 °C and strain rate range of 3 × 10−3 to 10 s−1. Strain rate sensitivity was calculated from the compression test data and mapped out in contour plots to determine the optimum regime of hot workability of vanadium. A high strain rate sensitivity of about 0.3 was obtained in the temperature and strain rate range of 1100 to 1400 °C and 3 × 10−3 to 1 s−1 for pure vanadium. Microstructures of the deformed samples showed features of dynamic recrystallization within the high strain rate sensitivity domain. Dynamic abnormal grain growth was observed at 1400 °C and strain rates of 0.1 and 1 s−1. The apparent activation energy of deformation was found to be 244 kJ·mol−1 and the stress exponent was about 3.4. The high values of activation volume suggest the barriers related to the dislocation intersection based process as the main rate controlling mechanism during the hot deformation of vanadium. The 〈100〉 and 〈111〉 fiber texture components evolved during the hot deformation of pure vanadium.