Metal Additive Manufacturing Conference - MAMC 2022

This work is a feasibility study for the usage of hybrid cast and WAAM manufactured components from a material science perspective. An A356 aluminium alloy in T6 condition was taken as cast substrate and a, regarding the chemical composition, identical AlSi7Mg wire was used to add structures. The welding was accomplished using a Fronius TPSi400 operating in CMT mode. Fundamental trends for the formation of the microstructure at changing welding parameters for the WAAM deposited material could be found. Two WAAM building strategies with different welding parameter sets were compared regarding their mechanical and microstructural properties. Additionally to microsection examination, tensile and fatigue strength testing was conducted. The better suitable set was used for the production of a hybrid cast and WAAM structure. The joint was found to show no lack of fusion or binding errors, but showed clustered pores. The mechanical properties of the hybrid structure was inferior to the solely additive and cast materials. Fracture analysis including SEM microscopy revealed the heat affected zone in the cast as the weakest part of the hybrid structure, with a significant drop in tensile and fatigue strength. Usage for commercial purposes is believed to be not possible at this stage, however utilisation in the components development process may already have advantages.