Fraunhofer Institute for Mechanics of Materials IWM
Laser shock peening (LSP) is a promising alternative to conventional shot peening for increasing the service life of components, particularly under fatigue loads. Shot peening is very cost-effective, but small changes in process parameters and wear can lead to undesirable weakening of the materials. LSP uses high-intensity laser pulses that generate plastic deformation on the component surface via shock waves, thereby building up compressive residual stresses that result in work hardening.
The materials science challenges associated with LSP primarily lie in the precise control of process parameters such as laser intensity, pulse duration, and repetition rate to specifically generate the desired compressive residual stresses and microstructural changes on the component surface. Additionally, the homogeneity of the residual stress profile must be ensured over large areas to avoid local weak spots. The rapid temperature change caused by the pulse can lead to undesirable microstructural changes and stress cracks, which must be controlled.
The Fraunhofer institutes IWM and IWS are collaborating to qualify the LSP process for specific industrial applications.
Fraunhofer IWS combines UKP laser sources with robot and scanner technologies for dynamic and large-area processing.