Research On Hot Plasticity Properties Of Hydrogenated Ti600 Alloy

Ti600 alloy is a kind of near-alpha titanium alloys and a kind of high temperature alloys.It shows excellent creep property and high temperature endurance when it is used at 600℃for the contents of rare earth element "Y".Therefore,this alloy is mainly used as components of high ratio engine,e.g.blades,compressors,and casings which work at severe working condition of high temperature,high pressure and high loads.Based on the system research about hot deformation of Ti600 alloy,through adding the "H" with different contents as the temporary elements to the alloy,the hot deformation behavior,and softening mechanisms were analyzed.And the processing maps of Ti600 alloy was established by dynamic materials model and the high temperature deformation characteristics have been analyzed by using processing map in detail.The following are major contents.(1) At given temperature and strain rate,with increase of hydrogen content from 0 to 0.5%,the flow stress of Ti600 alloy firstly decreased remarkably and then had a slight increase with a minimum value corresponding to an optimal hydrogen content. The optimal hydrogen content decreased with temperature increasing;And cuspidal yield points on the true stress-strain curves were found for Ti600 alloy with hydrogenation;(2) The result showed that the flow stress decreased with increasing temperature and decreasing strain rate for all tested Ti600 alloys(with and without hydrogenation);And the flow stress at optimal hydrogen content is equivalent to the value of Ti600 alloy without hydrogenation at temperature 150℃higher or strain rate two-order lower.(3) The hyperbolic sine Arrhenius constitutive equations of Ti600 alloy pre and post hydrogened were established and activation energy and related parameters were got;And the equation was verified by the experiment very well. (4) The processing map of Ti600 alloy hydrogened was firstly established with the theory of processing map;The results indicated the optimal power dissipation efficiency of Ti600 alloy(0.2%H) is between 0.4 and 0.5.