Near surface compressive residual stresses are known to improve the fatigue performance and damage tolerance of materials. In the aerospace gas turbine industry there is a compressive residual stress fields to extend the safe life time of a component is developing as a new field of research. Global near surface compressive stresses such as those produced by shot or glass bead peening have been used in service for a long time. The benefits of these stresses are not normally considered in the safety analysis of components; they normally act as an additional safety margin. The development of new surface treatment techniques capable introducing compressive residual stresses into specific locations has lead to increased industrial interest in the use of engineered compressive residual stresses for quantifiable life extension.