Fundamental Study on Cavitation Erosion Using a Magnesium Oxide Single Crystal.

Abstract

A magnesium oxide single crystal has simple characteristics with regard to a slip system and reveals clear dislocation etch pits. The (100) surface of this single crystal was exposed to vibratory cavitation to study the erosion behavior produced by bubble collapse. Dislocation rows were observed in [010] and [001] directions on the specimen surface and in the direction 45 degrees to the surface on the cross section. Cracks initiate in these directions to a depth of about 1 percent of the thickness of the deformed layer. Intensity of impact loads in cavitation bubble collapse is widely distributed from low to high, and many cyclic impact loads with low intensities are responsible for the material removal. It was concluded that the volume loss rate has a linear relationship with an increasing rate of dislocation-row density under various cavitation conditions.