Laser Shock Peening of Titanium Alloy for Improved Fatigue Resistance

Abstract

Fatigue in mechanical components remains a critical challenge, which can be mitigated by inducing subsurface compressive residual stress. Laser shock peening (LSP), a method utilizing high-energy laser pulses to generate shockwaves and residual stress (up to 2 mm), is investigated here. This study combines experimental LSP application, computational modeling via a 3D finite element approach (neglecting ablation and plasma effects), and fatigue testing on titanium specimens. Real-time stress measurements using photonic Doppler velocimetry (PDV) and residual stress profiling via drilling validated the model. PDV data correlated laser power density with pressure impulse parameters. Results demonstrated that optimized LSP treatment increased fatigue life by at least sevenfold compared to untreated specimens.