Patent ID: 6923877

Claim:
A method of improving the properties of a material of a workpiece by laser shock peening in which an overlay which is opaque to a laser beam, and an overlay which is translucent to said laser beam, are applied from a tool head to a surface of a workpiece, the translucent overlay being applied on top of and over the opaque overlay, a laser beam is then directed from said tool head at the said surface to which the overlays have been applied to vaporize the opaque overlay and laser shock peen the surface of the workpiece producing a region of compressive residual stress in said surface; wherein the opaque overlay, translucent overlay and the laser shock peening are applied concurrently, in a single operation by continuous relative movement between the workpiece and said tool head, as the surface of the workpiece is traversed so that as each point on the surface to be treated is traversed the opaque overlay, translucent overlay, and laser shock peening are applied sequentially to that point.