Abstract
When the α+β type titanium alloys are not subjected to the proper hot rolling process, the anisotropy in the microstructure appears even after the solution treatment and aging. This study was conducted to examine the anisotropy in mechanical properties of two heats (A and B) of Ti-6Al-4V alloy hot rolled plates which are subjected to the solution treatment and aging, and the mechanical anisotropy was correlated with the microstructural anisotropy. Tensile properties shows isotropic nature for both alloys. KIc and KIscc of alloy A are slightly reduced for transverse direction. On the other hand, KIc of alloy B is not reduced in T direction and KIscc is markedly increased for T direction. The KIscc in T direction is higher than KIc in the same direction. It was found that stress corrosion cracking of alloy B in transverse direction which was formed at the tip of prefatigue crack propagated with some branching along the primary α phase boundaries, leading to the apparent increase in KIscc.
