The mechanistic link between macrozones and dwell fatigue in titanium alloys

• Mechanistic link between macrozones and dwell fatigue damage is demonstrated based on the aspect ratio of macrozone. Preference sub-surface facets due to existence, causing quasi-plane strain conditions. High load shedding stress redistribution are related high-aspect-ratio macrozones. (>~4) particularly damaging when their c-axes within ~15° principal direction. This paper addresses role macrozone crystallography morphology in titanium alloy Ti-6Al-4V. Until now, relationship has remained mechanistically uncertain, but this establishes a mechanistic damage, explains preference for be sub-surface. It also outlines criteria which important potential definition (or microtextured region). long-axes orientated near-normal loading direction, such that basal planes oriented These may useful guiding development diagnostic experimental measurement tool (based EBSD or ultrasonics example) detection components.