Anisotropy of mechanical properties and influencing factors of hot rolling TC4 titanium alloy

Anisotropy of mechanical properties and influencing factors of hot rolling TC4 alloy were studied through quasi-static tests, dynamic compression tests, XRD, metallographic study, and electron microscopy analysis. Results indicate that the quasi-static and dynamic compression properties of 930℃ hot rolling TC4 titanium alloy exhibit obvious anisotropy: the rolling direction shows the best ductility and lowest yielding strength, while the transverse direction shows the highest yielding strength and worse ductility. The ductility and strength of the normal direction are both between the rolling direction and the transverse direction. Microstructure analysis results show that there are four factors which are responsible for the anisotropy of the mechanical properties. Firstly, after the hot rolling process, a weak plane texture was formed; secondly, the original grains were deformed into fibrous structure; thirdly the plate-like α clusters' normal axis tended to be parallel to the transverse direction of the rolling sheet; finally, a large amount of dislocations which are distributed in the grain were being parallel to the transverse direction according to the TEM results. The anisotropy of the mechanical properties is attributed to the above four factors.