Effects of hydrogen on hot deformation behavior of TC21 alloys

The effects of hydrogen on the transformation temperature and hot deformation behavior of TC21 alloys were investigated through microscopic analysis and isothermal compression tests respectively. The results indicate that the transformation temperature of TC21 alloys decreases significantly after hydrogenating, so that the transformation temperature of TC21 alloys containing 0.7%(mass fraction)H is 810°C, which decreases by 145°C compared with natural hydrogen. Meanwhile, the flow stress of TC21 alloys decreases effectively too after hydrogenating and the effects of hydrogen on flow stress become obvious with deformation temperature decreasing and strain rate increasing. The steady state stress of TC21 alloys containing 0.28%H reaches 202 MPa, which decreases by 28% compared with natural hydrogen. Under the same stress level, deformation temperature decreases by 40°C and strain rate increases one order of magnitude after hydrogenating.