Effects of laser energy on fatigue crack growth properties of 6061-T6 aluminum alloy subjected to multiple laser peening

Effects of laser energy on fatigue crack growth (FCG) properties of 6061-T6 aluminum alloy subjected to multiple laser peening (LP) were investigated. LP experiments and typical FCG experiments were performed on the compact tension (CT) samples. In order to reveal the enhancement mechanism of laser energy on FCG properties through residual stress (RS), a numerical model of effective stress intensity factor (SIF) was established. The results showed that compressive RS induced by LP can effectively decrease FCG rate and increase FCG lives of CT samples. The experimental results and numerical analysis correlated with each other.

► FCG rate decreases and FCG lives increase with the increase of laser energy.
► The reductions of FCG rate by LP in initial and final FCG stage are analyzed.
► Fatigue striation spacing of FCG region decreases with the increase of laser energy.
► Numerical model of FCG rate and FCG lives under RS induced by LP is established.
► Reasonable agreements are obtained between experimental and numerical results.