Microstructure and mechanical property of the novel Al17Cr17Co33Ni33 eutectic medium entropy alloy fabricated by powder plasma arc additive manufacturing

In this study, a new Al17Cr17Co33Ni33 eutectic medium entropy alloy (EMEA) is designed and successfully fabricated by powder plasma arc additive manufacturing (PPA-AM). The microstructural investigation reveals that the alloy consists of ordered hard body-centered cubic B2 phase and ordered soft face-centered cubic L12 phase. The microhardness of the alloy is 335.54 Hv. And comparing to PPA-AMed AlCoCrFeNi2.1 alloy, the designed alloy exhibits a high ultimate tensile strength of 1028 MPa and a high ductility of 19.09 % at the room temperature. And this represents a 17.89 %/32.57 % increase in ultimate tensile strength and ductility relative to a PPA-AMed AlCoCrFeNi2.1 alloy, respectively. This is attributed to the phase interfacial strengthening caused by finer lamellar thickness. And the mechniacal properties reveal the Al17Cr17Co33Ni33 alloy achieve the synergy of good tensile ductility and high fracture strength.