Influence of Silicon and Manganese on the Mechanical Properties of Additive Manufactured Cu–Al Alloys by Cold Metal Transfer Welding

Cu–6.5% Al alloys and Cu–6.5% Al alloys containing small amounts of silicon (Si) and manganese (Mn) were deposited using wire arc additive manufacturing (WAAM) by feeding two different components of wires simultaneously into the molten pool. The deposited alloys were homogenized by heat treatments at 800 °C (2 h). The effect of addition of Si and Mn on the microstructure and mechanical properties of Cu–6.5% Al alloys were investigated. Microstructural and formation of intermetallic compounds were studied. Results revealed that upon heat treatment, Si and Mn were able to restrain the dislocation movement due to the formation of second-phase particles. When compared to Cu–Al alloys, mechanical testing of the Cu–6.5% Al alloys having Si and Mn showed that hardness had increased by120 Hv, ultimate tensile strength (UTS) had increased by 284 MPa and yield strength (YS) had increased by 365 MPa, whereas its elongation (EL) had decreased by 22%.