Location dependence of microstructure and mechanical properties of Cu–Al alloy fabricated by dual wire CMT

To investigate the microstructure and mechanical properties at different deposition locations, an innovative dual wire Cold Metal Transfer (CMT) process was built to fabricate copper-aluminum alloy material with enhanced performances. Two commercial binary wires namely ERCuSi28L copper wire and ER4043 aluminum wire were fed into the common molten pool to build copper rich Cu–Al alloy samples by adjusting the wire feed speed of the two separate wire feeders. The deposited wall part showed good integrity and excellent mechanical properties, with only 15 MPa difference in ultimate tensile strength, 10 MPa difference in yield strength (YS) and 2% difference in elongation between the mechanical properties along the vertical directions. It was observed that the yield strength was higher than that of the commercially available T2-Cu. The average microhardness of the lower region, upper-middle region and upper region were 217.1 Hv, 226.8 Hv and 221.4 Hv, respectively. Four phases were detected in the deposited sample at different location, i.e. deposited height regions. From the results it is clearly seen that the dual wire CMT process has excellent potential to produce Cu–Al components with relatively low cost and reduced lead time, thus offering a new robust and viable manufacturing route. (paper)