An investigation was carried out to determine the effect of nodular cast iron (NCI), nickel aluminum bronze (NAB), and Monel 400 microstructures on their cavitation erosion behavior in natural seawater. The cavitation tests were conducted using cavitation-induced facility at a frequency of 20 kHz on detached specimens. Morphological examinations by the scanning electron microscopy (SEM) on cavitated specimen indicated that the surfaces of NCI, NAB, and Monel 400 became very rough with large-size cavity pits. Localized material removal on the NCI surface was due to ductile tearing and brittle modes of failure and that for NAB and Monel 400 was due to grain boundary attack and micro-galvanic activities between the different phases of these two alloys. It was determined that the mechanical action of the collapsing air bubbles on the surfaces of the three alloys was the main cause of metal loss.
Part of the book: Cavitation