Hot deformation behavior and microstructure evaluation of hydrogenated Ti-6Al-4V matrix composite

Ti-6Al-4V matrix composite reinforced with TiB and TiC particulates was prepared and hydrogenated. Isothermal compression tests were carried out at the deformation temperatures ranging from 750 °C to 900 °C and strain rate ranging from 0.01 s−1 to 1 s−1. The effects of hydrogen concentration, deformation temperature and strain rate on flow stress-strain curves and microstructure evaluation were studied. Hydrogen decreases the deformation temperature at least 100 °C or enables the composite to deform at a higher strain rate at the same flow stress level. Hydrogen improves dynamic recrystallization of α phase and accommodation deformation between reinforcements and matrix. Optimum hydrogen concentrations at different deformation temperatures were determined. The strain rate sensitivity index and apparent activation energy of the composite with 0 wt.% H and 0.35 wt.% H were calculated and discussed.