Fatigue crack growth behaviour in laser melting deposited Ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy

Experimental investigates on the fatigue crack growth behaviour along the deposition direction in a laser melting deposited Ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy under constant amplitude loading was carried out. A periodic fluctuation in the crack growth rate was observed which resulted from the layered structure with heat-affected bands (HABs). Macro- and micro-fracture characteristics are discussed in this paper to reveal the relationship between the crack growth rate fluctuation with the HABs and the crack deceleration and acceleration mechanisms. The crack growth rate fluctuations change little with the increase of crack lengths and the difference in test loads.