Stress corrosion behavior and mechanism of Ti6321 alloy with different microstructures in stimulated deep-sea environment.

The stress corrosion cracking (SCC) behaviors of Ti-6Al-3Nb-2Zr-1Mo (Ti6321, in wt %) alloy samples with equiaxed microstructure (EM), bimodal microstructure (BM) and Widmanstätten microstructure (WM) in simulated 3000 m deep sea environment were investigated using electrochemical tests, electron backscattered diffraction (EBSD), and so on. WM exhibits the best SCC resistance, which is attributed to its best self-healing ability, and is beneficial for the re-passivation of fresh metal at the crack tip. Besides, there is no obvious micro-texture region in WM with higher β phase, and α phase colonies hinder the dislocation movement, resulting in the lowest crack growth rate. • Deep-sea environment stress corrosion behaviors of Ti6321 alloy with different microstructures were investigated. • Ti6321 alloy with Widmanstätten microstructure has best stress corrosion resistance. • α phase colonies in Widmanstätten microstructure hinder the dislocation movement. • The best self-healing ability of Widmanstätten microstructure sample is beneficial for the re-passivation of fresh metal at the crack tip. [ABSTRACT FROM AUTHOR]