Toward the superior high-temperature strength of Al-5Fe alloy for powder bed fusion-laser beam: Stabilizing Al6Fe nanoprecipitate by Sc and Zr elements.

Existing additively manufactured aluminum alloys exhibit unfavorable tensile strength above 200 °C due to the strengthening phase coarsening, microstructure instability and cracking. This paper designed a novel Al-5Fe-1Mg-0.6Sc-0.3Zr alloy for powder bed fusion using laser beam (PBF-LB) with tensile strength of 189 MPa at 400 °C, which is the highest value reported. The main strengthening phases of the alloy were Al 6 Fe particle and nano-scaled L1 2 -Al 3 (Sc, Zr) precipitates. The exceptional high-temperature performance is attributed to high volume fraction (∼35%) of nanoprecipitates Al 6 Fe modified by Sc and Zr elements, showing enhanced thermal stability and refined particle dimension. The addition of Sc and Zr elements also significantly retards the phase transformation from Al 6 Fe to θ-Al 13 Fe 4 and inhibits brittle θ phase growth during thermal exposure. IMPACT STATEMENT: The paper designed a heat-resistant Al-Fe-Mg-Sc-Zr alloy with exceptional high-temperature performance (UST of 189 MPa at 400 °C) for PBF-LB. Adding Sc/Zr element can effectively enhance the thermal stability of Al 6 Fe and delays its transition to Al 13 Fe 4 phase. [Display omitted] [ABSTRACT FROM AUTHOR]