TABLE OF CONTENTS Laser shock peening (LSP) is an innovative surface treatment technique, which is successfully applied to improve fatigue performance of metallic components. After the treatment, the fatigue strength and fatigue life of a metallic material can be increased remarkably owing to the presence of compressive residual stresses in the material. The increase in hardness and yield strength of metallic materials is attributed to high density arrays of dislocations (Banas et al., 1990a, b) and formation of other phases or twins (Chu et al., 1999), generated by the shock wave.
The ability of a high energy laser pulse to generate shock waves and plastic deformation in metallic materials was first recognised and explored in 1963 in the USA (White, 1963). The confined ablation mode for an improved LSP process was established in 1968 (Anderholm, 1970). The LSP process was initially performed to investigate its application for the fastener holes in 1968 1981 at Battelle Columbus Laboratories (OH, USA) (Clauer et al., 1981). Since 1986, more systematic studies on applications of LSP have been carried out in other countries, such as France (Ballard et al., 1991; Peyre and Fabbro, 1995a, b), China (Zhang and Cai, 1996; Dai et al., 1997; Guo et al., 1999) and Japan (Sano et al., 1997).
Since the development of LSP, a number of patents have been issued addressing its strong interest for commercialisation. In 1974, the first patent was issued after the benefits of LSP were clearly identified (Mallozi and Fairand, 1974). For example, laser...
