Cavitation erosion of copper and copper-based alloys

Cavitation erosion studies of five multiphase copper-based alloys for a screw propeller application and of three alpha -solution alloys of comparative purpose have been carried out to determine the resistance of the allays to cavitation erosion and to understand the influence of the microstructure and/or composition of the alloys on the morphology of erosion damage. The experiments were conducted using a vibratory system. Erosion rates were measured, and the mechanism of damage under cavitation action was studied. No correlation between the cavitation erosion resistance (CER) and the mechanical properties of the alloys has been found. However, a good correlation between the resistance and work-hardenability, defined by means of stacking-fault energy (SFE), being a chemistry-dependent property, has been established for the alpha -solution alloys. A better CER can be expected for a lower SFE and higher work-hardenability. The resistance of the multiphase alloys in terms of chemical composition and mode of damage was discussed. An advantageous influence of nickel and aluminum and a low effectiveness of zinc on cavitation resistance have been outlined.