Wire arc additive manufacturing of low alloyed steels, copper aluminum alloys, and their bimetals

This study investigates the mechanical performance and microstructure of wire arc additive manufactured (WAAM) components using ER70S-6 low-alloy steel (LAS), CuAl8 aluminum bronze, and their bimetallic combination. WAAM was employed to fabricate both wall and bulk samples using a CMT (cold metal transfer) system. For LAS, the deposited microstructure featured Widmanstätten ferrite and grain boundary ferrite, with a maximum microhardness of 259 HV and a failure load of 4726 N. The CuAl8 alloy exhibited a β-phase along grain boundaries and α-phase within grains, achieving a maximum hardness of 137 HV and a failure load of 1690 N. In the bimetallic configuration (CuAl8–steel), strong metallurgical bonding was achieved at the interface, with refined grains in the dilution zone contributing to enhanced local hardness. The bimetallic samples demonstrated a maximum microhardness of 131 HV and a failure load of 1939 N. These findings highlight the potential of WAAM for fabricating monolithic and bimetallic parts suitable for marine and structural applications requiring localized strength.