(V) The roadmap to improve the printability of non-castable alloy for large-scale additive manufacturing production

The non-castable Al alloy can hardly be printed by powder bed fusion (PBF) additive manufacturing, because of the serious hot cracking problem induced by the wide solidification range. Here, the in-situ mixing salt method in combination with gas atomization, which is suitable for mass additive manufacturing production, is first proposed to produce the powders of conventional non-castable alloy, behaving with excellent printability. The non-castable Al4Cu1.6Mg0.6Mn (A0T) alloy and the pre-decorated TiB₂/Al4Cu1.6Mg0.6Mn (A2T) alloy powders are prepared and their printability is tested. The results show that the cracks in the printed A2T alloy are eliminated caused by the introduction of the TiB₂ particles. The average grain size of the printed A2T alloy is ~5.2 μm, significantly reduced from ~38.8 μm in the printed A0T alloy. The novel fine equiaxed-columnar bimodal grain microstructure in the printed A2T alloy improves the ultimate tensile strength to ~371.6 MPa and total elongation at fracture to ~7.1%. This manuscript suggests the roadmap to improve the printability of the non-castable alloy for mass additive manufacturing production.