Study of mechanism of strengthening materials with laser shock processing

The material of surface layer absorbs the energy of laser and produces plas ma, when the high power laser radiates the surface of material. The plasma blows up and produces an intense shock wave. When the surface of material i s covered with a confining medium and an absorptive coating layer, the shoc k wave can be strengthened greatly. Therefore a huge momentum is exerted on the surface of material. There is a plastic deformation layer in the mater ial when the shock stress exceeds the dynamic yield strength of material. D ue to the residual compressive stress, the high density of dislocation in t he plastic layer, the anti-fatigue life of material is prolonged.