Enhanced extra-long life fatigue resistance of a bimodal titanium alloy by laser shock peening

Abstract Ultrasonic fatigue tests were performed on notched specimens to investigate high and very high cycle fatigue behaviors in the laser shock peened region of a compressor blade titanium alloy (Ti–8Al–1Mo–1V). The plastic deformation and compressive residual stress, induced by the laser shock peening (LSP), present gradient distributions along the depth direction. High-angle grain boundaries (HAGB, >15°) are increased by deformation twins, which are introduced into primary α phases during the plastic deformation. The enhancement in fatigue resistance is ascribed to the comprehensive retardation effects of the compressive residual stress, high-density dislocations, and HAGBs.