CoNiFeNb_0.45 eutectic multi-principal element alloy with excellent mechanical properties and corrosion resistance

A novel CoNiFeNb_0.45 eutectic multi-principal element alloy (EMPEA) with a dual-phase structure is designed and synthesized by arc melting and suction casting. The compression strength of the CoNiFeNb_0.45 EMPEA is 2.5 GPa at room temperature and high compression strength (1.2 GPa), furthermore, the excellent ductility with 40% fracture strain are maintained at 700 °C. The dislocation walls in the soft fcc phase provide the CoNiFeNb_0.45 EMPEA with high ductility and work hardening, while the dislocations pined in the fcc/laves phase boundaries provide the alloy with high strength. The CoNiFeNb_0.45 EMPEA also has excellent corrosion resistance in 3.5 wt% NaCl at room temperature as manifested by a corrosion rate of merely 0.003 mm/y and activation energy of corrosion of 53.6 kJ/mol.