Wire arc additive manufacturing of ZL205A: Heat input effect on the forming quality, pore defects and mechanical properties

The magnitude of heat input (HI) plays a pivotal role in determining the deposition quality of wire arc additive manufacturing (WAAM) components. This article studies the effects of high and low HI on the forming quality, microstructure, pore defects, and mechanical properties of ZL205A parts, providing a theoretical foundation for choosing optimal HI parameters in the utilization of WAAM technology to fabricate ZL205A structural components. In this study, four thin-walled walls, SP1, SP2, SP3, and SP4, were manufactured with HI of 300.12, 200.08, 163.70, and 138.51 J/mm, respectively. The findings show that the SP4 has the least side forming error, and the maximum deposition efficiency, resulting in the best forming quality. From microstructural studies，SP4 has the lowest average grain size, 72μm. The quantity of θ phases (Al₂Cu) on the grain boundary and the quantity and size of θ' phases in the middle and bottom grains both diminish with decreasing HI. As the HI decreases, the porosity of the four samples shows a trend of first decreasing and then increasing, with the highest being 1.41 % of the SP1. This change is explained from the four stages of bubble nucleation, growth, detachment, and escape. Reducing HI can significantly improve the ultimate tensile strength (UTS), and yield strength (YS) of the specimen. The SP4 has the highest UTS and YS, which are 232.99 MPa and 101.20 MPa, respectively.