Micromechanism of High-temperature Fatigue Properties of Inconel 718 Nickel-based Alloy Treated by Laser Peening

The fatigue lives of IN718 alloy treated by laser peening (LP) were examined at high temperature. The microstructural response of the fatigue specimens was revealed. The results show that LP can refine the grain size, and produce new dislocation structures. The mechanical twins in the high-power LPed specimens can interact with other dislocations to refine the grains. A special "dislocation-precipitate" entanglement in the high-temperature fatigue LPed specimens at 700 was helpful to form a more effective pinning effect on the dislocation movement and thus preventing the initiation and propagation of fatigue cracks.