Additive Friction Stir Deposition of Aluminum-Cerium Alloys for Aerospace Structural Applications

Al-Ce alloys, known for their excellent creep resistance and thermal stability due to the Al11Ce3 phase, were optimized using CALPHAD simulations to incorporate in addition solid solution and precipitation strengthening. Additive friction stir deposition (AFSD) was used to fabricate 3D builds from cast material, refining the grain size and microstructure by fragmenting Al11Ce3 lamellae into smaller, uniformly dispersed particles and inducing Al3Sc nanoprecipitates during deposition. Microstructural and mechanical analyses revealed remarkable strength-ductility synergy with the as-deposited properties (YS 400 MPa, TS 530 MPa, ductility 13%) far surpassing those of cast, extruded, HIPPed, or LPBF/DED Al-Ce alloys. Fatigue, creep, and corrosion properties were also determined and found to surpass those of many commercial aluminum alloys. The strategy of AFSD-specific process dynamics, such as intense deformation and localized high temperatures, to enable in-situ precipitation and microstructural refinement with exceptional mechanical properties, offers a transformative pathway for designing energy-efficient, high-performance materials.