Thermal Deformation Behavior and Microstructure of TC4 Titanium Alloy in Two-phase Region

Author of the article:LI Dongkuan 1 , GUO Yan 2 , YANG Lixin 1 , ZHANG Yufen 1 , WANG Deyong 1 , WANG Tao 3

Author's Workplace：1. Shenyang Aircraft Industry (Group) Co., Ltd.,; 2. First Military Representative Office of the Air Force Equipment Department in Shenyang Area, 3. Western Superconducting Materials Technology Co.,

Key Words：TC4 titanium alloy; thermal deformation; microstructure

Abstract：Taking TC4 titanium alloy in the two-phase region as the research object, combined with the production test, the
thermal simulation test was carried out on two titanium alloys with different microstructure states, and the constitutive
equation was established. The microstructure evolution model of TC4 titanium alloy was established by studying the effects
of different temperature, strain rate, deformation degree and forging deformation pass on microstructure. The results show
that the thermal deformation behavior of titanium alloys with two different microstructure accords with the Hansel-Spittel
constitutive equation, and the established constitutive equation can describe the thermal deformation behavior of titanium
alloys effectively. Under the condition of 930 ℃ to 975 ℃ and 0.1 s -1 to 1.0 s -1 strain rate, the true stress decreases with the
increase of temperature and increases with the increase of strain rate when the true strain changes phase. The higher the
spheroidization degree of α phase in the initial microstructure, the higher the peak stress corresponding to the true
stress-strain curve. Under different thermal deformation conditions, with the increase of strain rate, the α phase grain
becomes smaller, and the α phase content doesn ’ t change. With the increase of deformation temperature, the equiaxed α
phase decreases obviously. The α phase grain is smaller with the increase of deformation degree. As the forging passes
increase, the α phase in the two-phase region changes from long strip to equiaxed structure of about 10 μm