Cavitation resistance of powder metallurgy aluminum matrix composite with AlN dispersoids

The cavitation erosion resistance of P/M aluminum alloy sintered composite with AlN dispersoids, prepared via the in situ synthesis and the conventional premixing process, was evaluated by using a magnetostrictive-vibration type equipment. In situ synthesized AlN particles were effective for the improvement of the erosion resistance of the composite because of their good bonding with the aluminum matrix. The additive AlN by the premixing process were easily detached from the specimen surface due to the insufficient coherence with the matrix, and caused the poor resistance. The cavitation resistance also depended on the porosity of the sintered composite. The continuously opened pores accelerated the wear phenomena by the cavitation due to the high pressure attack on the primary particle boundaries of sintered materials in the collapse of the bubbles.