Microstructure, hardness, and electrical resistivity of Al-Cu alloy fabricated via wire arc additive manufacturing

Additive manufacturing (AM) techniques allow for greater design freedom than is possible with conventional manufacturing processes. Components fabricated via AM can be compact and more potent for electrical applications. This study used cold metal transfer (CMT) based wire arc additive manufacturing (WAAM) to build the WAAM 2319 wall. The microstructure is mainly composed of equiaxed and columnar dendrites along with a small fraction of pores. Precipitated θ phases formed due to complex thermal cycles during WAAM. The hardness of the WAAM 2319 alloy ranged between 68 HV0.2 to 86 HV0.2. The electrical resistivity of WAAM 2319 was 6.72±0.23 µΩ-cm resulting in the reduced conductivity of 25.66±1.10%IACS compared to the wrought AA2219 alloy having 30%IACS. The decrease in conductivity is attributed to the presence of coarse precipitates along with dendritic microstructure and copper solute concentration. Thus, WAAM-processed Al-Cu alloys can be used for future electrical applications.