  In this paper we report on the competition in metal surface hardening between
the femtosecond shock peening on the one hand, and formation of laser-induced
periodic surface structures (LIPSS) and surface oxidation on the other hand.
Peening of the stainless steel AISI 316 due to shock loading induced by
femtosecond laser ablation was successfully demonstrated. However, for some
range of processing parameters, surface erosion due to LIPSS and oxidation seem
to dominate over the peening effect. Strategies to increase the peening
efficiency are discussed.
