Microstructure evolution and hot deformation behavior of high Nb contained titanium aluminides hydrogenation at high temperature

Abstract:

This study focused on the hydrogen absorption behavior of high Nb contained titanium alumindies at high temperature, the effect of hydrogen on microstructure evolution and hot deformation behavior the alloy were studied. The results show that hydrogen absorption in titanium aluminides is endothermic reaction, hydrogen contentin the alloy increases with increasing of hydrogenation temperature, hydrogenation time and hydrogen flow rate which is sensitive to hydrogenation temperature.The lamellar space of hydrogenated alloy is coarsened after hydrogenation at 1200℃, the content of B2 phase is more in hydrogenated alloy as hydrogen is beta stabilized element. The interface of lamellar colonies is smoothed when hydrogenation above 1280℃as hydrogen reduces the interface energy. Hydrogen has a great effect on hot deformation of titanium alumnides, the peak stress decreases by 40% after hydrogenated with 0.043wt% hydrogen under strain rate of 0.01s_-1 at 1200℃.Hydrogenation at high temperature is an effective method to improve the hot workability of titanium aluminides