Process-specific design strategy enables exceptional as-deposited strength-ductility synergy in novel Al–Ce alloys via additive friction stir deposition (AFSD)

Abstract

A process-specific alloy design strategy was employed to achieve exceptional as-deposited strength-ductility synergy in Al–Ce alloys, eliminating the need for post-aging treatments. Al–Ce alloys, known for their excellent creep resistance and thermal stability due to the Al 11 Ce 3 phase, were optimized using CALPHAD simulations to incorporate solid solution and precipitation strengthening in addition to composite strengthening from the Al 11 Ce 3 phase. Additive friction stir deposition (AFSD) was used to fabricate 3D builds from cast material, refining the grain size and microstructure by fragmenting Al 11 Ce 3 lamellae into smaller, uniformly dispersed particles and inducing Al 3 Sc nanoprecipitates during deposition. Microstructural and mechanical analyses revealed remarkable improvements: while the cast alloy fractured at 230 MPa with no ductility, the AFSD alloy achieved a yield strength of 385 MPa, UTS of 530 MPa, and 12.6% plastic strain. These as-deposited properties surpassed those of cast, extruded, HIPPed, or LPBF/DED Al–Ce alloys, including the previous results obtained after aging. This strategy leverages AFSD-specific process dynamics, such as intense deformation and localized high temperatures, to enable in-situ precipitation and microstructural refinement with exceptional mechanical properties, offering a transformative pathway for designing energy-efficient, high-performance materials. • Achieved exceptional strength-ductility synergy in Al–Ce alloys via AFSD. • Process-specific alloy design eliminated the need for post-aging treatments. • In situ Al 3 Sc precipitation and Al 11 Ce 3 refinement enhanced mechanical properties. • Demonstrated energy-efficient alloy design for additive manufacturing applications.

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