Effect of Strain Rate on Stress Corrosion Cracking Behavior of Alloy 718 in High Temperature Water

The influence of different strain rates on the stress corrosion behavior of 718 alloy was investigated using slow strain rate testing (SSRT). The micro chemical composition of the fracture surface and crack tip was analyzed using microscopic characterization techniques. And the stress corrosion crack initiation and propagation mechanism of 718 alloy was studied. The results indicate that strain rate could significantly affect the mechanical properties and fracture mode of 718 alloy in high-temperature water, and reducing strain rate could greatly enhance stress corrosion sensitivity. The SCC behavior of 718 alloy was governed by both oxidation and stress, with a distinct partitioning between these factors during initiation and propagation.