Abstract

Nickel aluminium bronze is a high value, high performance alloy for sea water applications, which was originally developed for the casting process, and is the most widely used alloy for components such as the largest propellers in commercial and defense vessels. However, recent research has shown that the properties of this alloy can be further improved by the additive manufacturing process, due to the refinement of its complex microstructure. The microstructure of this sophisticated alloy includes several precipitates, including a eutectoid microconstituent, and it is possible to benefit from heat treatment. In additive manufacturing, these phase transformations are profoundly altered due to the increased cooling rate and repeated heating as the layers are deposited. The ongoing work presented here is oriented to developing a better understanding of the phase transformations in additive manufacturing and their relationship with the thermal regime, the choice of processing parameters and the performance of the material, including mechanical properties and an innovative approach to fracture toughness.