Laser Cavitation Peening Using a Nd:YAG Laser and a Fiber Laser

Cavitation is a harmful phenomenon for hydraulic machineries such as pumps and valves etc., as it causes severe erosion by impacts at cavitation bubble collapses. However, the cavitation impacts can be utilized for mechanical surface modification in the same way of shot peening. A peening method using cavitation impact is called as “cavitation peening”, especially cavitation peening using a pulsed laser is named as “laser cavitation peening”. Laser cavitation peening can improve fatigue strength of additively manufactured (AM) metals. However, it takes time to treat, as the repletion frequency of Q-switched Nd:YAG laser is slow such as 10 Hz. In the present paper, laser cavitation peeing using a fiber laser whose maximum frequency was 50 kHz was demonstrated.