Selective laser melting of nickel aluminium bronze

Nickel aluminium bronze (NAB) is widely used in naval applications due to its combination of excellent corrosion resistance in sea water applications and medium strength levels. These alloys have complex microstructures of α and β solid solution phases together with different forms of the intermetallic κ phase. In this work, selective laser melting (SLM) of Cu-9.8Al-5.2Ni-4.6Fe-0.3 Mn (wt. %) NAB powder was optimised to produce dense NAB specimens. The as-built specimens consisted of martensitic microstructures. Through the application of various heat treatment conditions, α + κ microstructures typical of traditional NAB alloys, were obtained and the mechanical and electrochemical properties were characterized. A heat treatment at 700 °C for 1 h on the as-built structure yielded NAB specimens with superior corrosion performance and mechanical properties than conventional wrought or cast NAB. This work shows that SLM of NAB alloys is possible and the components obtained exhibit properties at least as good as their cast or wrought counterparts. This opens up the possibility of using NAB components fabricated by SLM in engineering applications.