Selection Of High Temperature Deformation Model Of Ti-45Al-8.5Nb-Y Alloy And Prediction Of Stress And Strain

High Nb containing TiAl based alloy has widely promising application in the aerospace and automotive industries owning to its excellent high temperature strength and high temperature oxidation resistence.In this paper,a high Nb containing TiAl based alloy with a compostion of Ti-45Al-8.5Nb-Y（at.%）was fabricated,the curves of Ti-45Al-8.5Nb-Y alloy at different temperature and strain rate were constructed,and three high temperature deformation models（Ludwik,Zener-Hollomon and Hensel-Spittel）were used to calculate the stress of Ti-45Al-8.5Nb-Y alloy.The experimental data of high Nb containing TiAl alloy Ti-45Al-8.5Nb-Y in the gleeble 1500 test machine for high temperature compression heat physical simulation experiment,the test temperature range of 1200℃,1225℃,1250℃and 1275℃,the test strain rate range of 0.01s^-1,0.05s^-1and 0.1s^-1,was obtained.Then the true stress-strain curves were fitted by using the experimental data and the change of the curve has been analyzed.The Ludwik model has simple structure and convenient usability.And the predicted value has a better matching with the experimental stress,the corresponding coefficient of association is 0.96476.However,for the lack of temperature parameter,the other deficiency of Ludwik model is the error between the predict value and the experimental value at high strain rate is big.The Zener-Hollomon model which does not consider the influence of strain on stress has limited prediction ability and only predicts the stress at monotonous decline portion.The prediction has a lower correlation with the experiment value.The Hensel-Spittel model which comprehensively considers the influence of strain,strain rate and temperature has a better prediction ability.The Hensel-Spittel model could predict the unobtainable curves of Ti-45Al-8.5Nb-Y alloy at severe test condition,and guide the hot deformation of Ti-45Al-8.5Nb-Y.