DIC‐Based Studies on the Crack Growth Behavior of TA15 Titanium Alloy Repaired by Laser Deposition

ABSTRACT Following laser deposition repair, TA15 titanium alloy exhibits a heterogeneous structure. Using digital image correlation (DIC), this study investigates the fatigue crack growth behavior and mechanism in the repaired zone versus the substrate zone. Results show the repaired zone has a lower fatigue crack growth rate than the substrate zone. Crack tip strain increases significantly with crack length, with a higher strain values in the repaired zone. Strain rings reveal greater plastic accumulation in the substrate zone, correlating with its faster crack growth. Furthermore, crack opening displacement (COD) and crack tip opening displacement (CTOD) effectively characterize the fatigue crack growth rate and can substitute for the stress intensity factor range.