Additive manufacturing-based combinatorial approach to improve bonding strength and heat transfer performance in wrought-cast Al compound casting

We improved the interfacial bonding strength and heat transfer performance between wrought and cast Al alloy parts by implementing an interfacial Al-Si-Zn-based alloy coating layer. An additive manufacturing (AM)-based combinatorial experiment was employed to determine the optimal composition of coating layers. Various compositional combinations of Al-Si-Zn layers were deposited onto an Al plate using a multi-nozzle direct energy deposition system, and the wetting behavior of the cast materials onto the combinatorial samples was examined to select the best composition of the coating layer. The selected coating layer was sprayed on the cooling pipes, and an actual-scale motor housing integrated by the pipe was produced by a compound die casting. The Al-Si-Zn coating layer caused the surface of the coating layers on pipes to partially melt when in contact with the molten alloy during the casting. Consequently, a reactive layer was rapidly formed between the coating and cast materials before solidification. As a result, the interfacial bonding strength increased to 13 MPa and heat transferability between the wrought and cast materials was improved. Therefore, we described the AM-based combinatorial exploring method for the interfacial coating layer to overcome the interfacial issues between the wrought and cast materials of compound casting.