Influences of microstructures and macrozones on the stress corrosion cracking sensitivity of a near alpha titanium alloy

In this study, we investigated stress corrosion cracking (SCC) behaviors in a near alpha titanium alloy (Ti-6Al-3Nb-2Zr-1Mo) with distinct microstructures and microtextures. By analyzing fracture surfaces, crack growth paths, and grain orientations, we found that the SCC crack growth rate increased with an increase in the volume fraction of the primary α_p phase, due to elevated crack initiation density and concentrated grain orientations. Additionally, SCC cracks exhibited a preference for propagating along boundaries between neighboring soft macrozones (easy for slip) and hard macrozones (relatively hard for slip), as well as through macrozones favorable for slip.