Crack appearance of a laser shock-treated single crystal nickel-base superalloy after isothermal fatigue failure

Isothermal fatigue testing was conducted on single crystal nickel-base superalloys. Distinct cracking behaviors were found to occur in the specimens treated by different laser shock processing (LSP) technologies. A crack generally initiates from the casting micropore. For the well surface strengthened specimens suffered high laser shock intensities, the crack initially grows along one or more of the {111} planes and falls on the edge of the cylindrical specimen. For the poorly strengthened specimens, the final fracture area is usually located inside.