Laser-beam powder bed fusion of Al–Fe–Cu alloy to achieve high strength and thermal conductivity

Abstract

Laser-beam powder bed fusion (PBF-LB) technique was used to produce an Al–2.5 %Fe–2 %Cu ternary alloy, featuring a two-phase eutectic composition of α-Al/Al₂₃CuFe₄ in non-equilibrium solidification, as determined by thermodynamic calculations. The specimen manufactured by PBF-LB exhibited a high tensile strength exceeding 350 MPa and a low thermal conductivity of approximately 140 W m⁻¹ K⁻¹. Subsequent annealing at 300 °C improved the thermal conductivity to 175 W m⁻¹ K⁻¹ without compromising the strength. This improvement was attributable to forming numerous Al₂₃CuFe₄ nanoprecipitates, which consumed solute elements. By appropriately managing the factors contributing to strengthening, a superior strength–conductivity balance can be achieved by implementing post-heat treatments.