EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Alloy development efforts in the Al-Co-Cr-Fe-Ni and Al-Cr-Fe-Ni systems have shown that novel duplex materials composed of a mixture of FCC and BCC phases can be obtained. Among them, the Co-free alloys with a composition close to AlCrFe2Ni2 are interesting candidates for casting, forging and powder based additive manufacturing routes. This is due to their strength-ductility balance that can be tailored by adjusting the relative phase fractions of FCC and BCC through compositional modifications and heat treatment.

Within the frame of a joint European project, we aimed at developing the high entropy alloy around the composition of AlCrFe2Ni2 with the use of prealloyed and elemental powder blending. We optimized the process parameters for powder based additive manufacturing, specifically for laser powder bed fusion (LPBF). In this presentation we will report on:
(i) The powder properties and the critical process parameters for minimizing defect formation during LPBF of AlCrFe2Ni2.
(ii) The alloy microstructure in as-built and heat treated conditions corresponding to alloy compositions with different Aluminum content.
(iii) The mechanical properties obtained by tensile testing of the specimens after heat treatment and their comparison with those of reference duplex steels.

We will discuss the origin and the transformation pathways which lead to the different microstructure features and their effect on mechanical properties. At last, we will give an outlook to potential applications of the novel alloy and present a demonstrator part built with LPBF.