Improvement of Fatigue Strength of Light Metallic Materials by Cavitation Shotless Peening

Cavitation normally causes severe damage in hydraulic machinery such as pumps, valves and so on. However, cavitation impact can be utilized to surface treatment to improve fatigue strength of metallic materials in the same way as shot peening. A peening method using cavitation impact was named as “cavitation shotless peening” or “cavitation peening” as shots are not required. As increase of surface roughness induced by cavitation shotless peening was relatively small comparing with that of shot peening, improvement of fatigue strength of light metallic materials would be better than that of shot peening. In the present paper, the aluminum alloy and the magnesium alloy treated by cavitation shotless peening were tested by a rotating bending fatigue test. It was revealed that the fatigue strength of the aluminum alloy JIS AC4CH and magnesium alloy JIS AM60B were improved 40 % and 20 %, respectively.