Cavitation erosion of aluminum alloys was investigated by a magnetostriction vibratory apparatus in which the stationary specimen was fixed beneath the horn. The effects of the test liquid, the space between the horn and the specimen, and the temperature on the erosion were clarified. A suitable test condition was selected from the results obtained, and several commercial aluminum alloys were studied. The resistance to the cavitation erosion of die-cast aluminum alloys was higher than those of the gravity castings and the wrought aluminum alloys with the same hardness, because the hard chilled layer with fine microstructure was formed on the surface. The damage of the die-cast aluminum alloys tended to decrease with the increase of Si and solid solution strengthening elements including Cu and Mg. In the case of the same composition, when the Si particles were smaller and finely dispersed, the damage of the cavitation decreased. Based on these results, the rapid solidified Al-Si-Fe-Cu-Mg powders with a large amount of Si were produced. The aluminum alloys, made by powder metallurgy process, were found excellent in mechanical properties, as well as the resistance to cavitation erosion.
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