Additively manufactured high strength aluminium (Al) alloy AA7075 was prepared using selective laser melting (SLM). High strength Al-alloys prepared by SLM have not been widely studied to date. The evolution of microstructure and hardness, with the attendant corrosion, were investigated. Additively manufactured AA7075 was investigated both in the “as-produced” condition and as a function of artificial ageing. The microstructure of specimens prepared was studied using electron microscopy. Production of AA7075 by SLM generated a unique microstructure, which was altered by solutionising and further altered by artificial ageing—resulting in microstructures distinctive to that of wrought AA7075-T6. The electrochemical response of additively manufactured AA7075 was dependent on processing history, and unique to wrought AA7075-T6, whereby dissolution rates were generally lower for additively manufactured AA7075. Furthermore, immersion exposure testing followed by microscopy, indicated different corrosion morphology for additively manufactured AA7075, whereby resultant pit size was notably smaller, in contrast to wrought AA7075-T6.

The microstructure and electrochemical properties of additively manufactured 22Cr duplex stainless steel (DSS) and 25Cr super duplex stainless steel (SDSS) produced by laser-powder bed fusion (L-PBF) are reported herein. The as-built microstructure is fully ferritic, while a 50/50 ferrite-austenite phase ratio was achieved by post heat treatment. The electrochemical response of DSS and SDSS prepared by L-PBF was investigated using cyclic potentiodynamic polarization (CPP) tests in 0.6 M NaCl solution and compared with the wrought counterparts. Both 22Cr DSS and 25Cr SDSS prepared by L-PBF showed comparable electrochemical response to their corresponding wrought alloys at room temperature. The findings herein demonstrate the feasibility of additive manufacturing as applied to DSS.