A novel corrosion resistant NiFeCrAlTi eutectic high entropy alloy with high strength and ductility

We present a novel corrosion resistant Ni42.6Fe24.6Cr16.4Al13.4Ti3 eutectic high entropy alloy (EHEA), which consists of FCC(L1(2)) phase and BCC(L2(1)) phase. The FCC and BCC phases contain numerous nano-precipitates, with sizes of similar to 10 nm and 80 nm, respectively. The as-cast EHEA exhibits exceptional mechanical properties with a yield strength of similar to 730 MPa, an ultimate tensile strength of 1220 MPa and elongation of 25 %, surpassing those observed in other as-cast EHEAs. The excellent mechanical properties are attributed to the extensive dislocation activities and precipitation strengthening in both BCC and FCC phases, as well as hetero-deformation induced (HDI) strengthening. Besides, the Kurdjumov-Sachs (KS) orientation relationship between adjacent phases promotes the cooperative deformation of both constituent phases, thereby enhancing the ductility of the EHEA.