Enhanced high-temperature strength and ductility of wire arc additive manufactured Al–Ce–Mg alloys with fine α-Al/Al₁₁Ce₃ eutectics

Here, wire-arc additive manufacturing (WAAM) is employed to fabricate Al–Ce–Mg heat-resistant aluminum alloy, considering its capability to manufacture large complex structures more efficiently. Large-sized faceted Al₁₁Ce₃ intermetallic compounds are formed in the as-cast alloy with a hypereutectic microstructure. The microstructure is transformed to a eutectic microstructure by non-equilibrium solidification of WAAM, consisting lamellar α-Al/A1₁₁Ce₃ eutectics. The WAAM alloy shows enhanced mechanical strength and ductility at 200 °C, compared with the as-cast alloy. The significant improvements of ultimate tensile strength and elongation for the WAAM alloy are correlated with its higher strain hardening rate, along with the transition from cleavage fracture to dimple fracture. The cracking of Al_l1Ce₃ particles occurs preferentially during the elastic deformation stage, as revealed by in-situ testing, and the strain hardening capability of the as-cast alloy is reduced. Pore defects, 0.15 % in volume fraction, are produced via WAAM processing, and the plastic deformation promotes the pore growth and mergence, increases the pore volume fraction, and decreases the pore sphericity. Our results demonstrate that WAAM is strongly attractive for the fabrication of Al–Ce–Mg alloys, due to the enhanced high-temperature strength-ductility synergy.