Aluminum alloy friction stir additive manufacturing technique with continuous feedstocks

In order to solve the inherent issues of discontinuous feedstocks and kiss bonding in the solid-state additive manufacturing process, a novel friction stir additive manufacturing with continuous feedstocks was proposed. The applied tools including a storage cavity with a feeding hole and a screw topology which can thermo-plasticize and continuously extrude the Al-Si alloy wire were designed. The results showed that the Al-Si alloy wire was conveyed to the feeding hole into the storage cavity, and the pin continuously thermo-plasticized and extruded downward Al-Si alloy materials. The probes at the bottom of the pin were used to stir and process the thermo-plasticized materials, which can extremely improve the bonding efficiency of the interfaces. The friction stir additive manufacturing with continuous feeding aluminum alloy wires was successfully realized, and the inherent issue of kiss bonding of interfaces between layers was solved. The thickness of the individual layer was about 1.2 mm. The tensile strength and elongation of the Al-Si alloy formed part along the stacking direction have little differences, which were 207.1 ± 3.2 MPa and 19.6 ± 5.3%, respectively. Friction stir additive manufacturing with continuous feedstocks can provide a feasible process method towards full solid-state additive manufacturing of large aluminum alloy parts.