Cavitation Typology in the Marine Environment in Copper-Based Alloys: Particular Case of Copper, Brass, NAB (Nickel Aluminium Bronze) and MAB (Manganese Aluminium Bronze)

Cavitation has been studied in the field of naval engineering as an important problem, which occurs frequently and is not completely solved at present, despite the numerous computer programmes and mathematical models for its study, prediction and prevention. It should be pointed out that there are few studies that deal with the impact on the different copper-based alloys used for the manufacture of components such as naval propellers, valves, etc., taking into account real service conditions. In this work, the cavitation behaviour of different copper-based systems in natural seawater will be studied using an ultrasonic bath. The geometry and different behaviour of the bubble impact on the surface of each of the alloys will be determined, relating it to their microstructures, as well as their physico-chemical behaviour and evolution of the damage over time. It has been observed that the most susceptible material is manganese aluminium bronze, MAB, due to both, (i) the size, shape and chemical composition of its intermetallic phases, and (ii) to its worse resistance to corrosion in the seawater.