Mechanical surface treatments, such as shot peening or deep rolling, are well known processes to improve the fatigue strength of metallic components. This is due to favourable microstructural alterations in relatively thin surface layers connected with the surface treatments applied as a consequence of near surface inhomogeneous plastic deformations. Typical examples are shown, demonstrating the fatigue strength increase of mechanically surface treated specimens. In the case of light weight materials, e.g. magnesium, aluminium or titanium base alloys, process parameters have to be well adapted in individual cases to achieve optimum near surface materials states, taking the wide range of mechanical properties attainable with such materials as a result of their specific microstructures into account. In this paper, a short survey of characteristic examples is given, demonstrating the influence of process parameters and microstructures on near surface materials properties resulting from mechanical surface treatments. Depth distributions of macro and micro residual stresses are analysed together with microstructural observations. An important point for the effectiveness of mechanical surface treatments is the stability of the near surface materials states during loading history. This aspect is treated for the case of fatigue loading.
展开▼
