Net-Form Manufacturing of Aluminum Components: the Dependence of Processing Parameters on Component Quality

High precision droplet-based net-form manufacturing of structural components is gaining considerable academic and industrial interest due to the promise of improved component quality resulting from rapid solidification processing and the economic benefits associated with fabricating a structural component in one integrated operation. In this work circular cylinders that are 35 mm in diameter and up to 11 cm in height are fabricated in their net-form by depositing molten 2024 aluminum alloy droplets onto a flat-plate substrate and building the cylinder layer by layer in the direction of its long axis. Droplets are generated from capillary stream break-up from 150-micron diameter orifices at rates typically on the order of 18,000 droplets/second depending on stream conditions. The mechanical and microstructural characteristics of the net-formed components are studied and their dependence on the processing parameters such as droplet temperature, substrate temperature and mass flow rate delivered to the substrate is ascertained.