The enhanced corrosion resistance and mechanical properties of AlCoCrFeNi2.1 eutectic high entropy alloy by addition of Mo element

In this work, an innovative strategy is proposed for synergistically enhancing the mechanical strength and corrosion resistance (in 3.5 wt% NaCl solution) of the AlCoCrFeNi 2.1 eutectic high-entropy alloy (EHEA) through precise molybdenum (Mo) alloying. The results demonstrate that the optimal Mo addition (x = 0.3) simultaneously enhances both mechanical properties and corrosion resistance. Specifically, the AlCoCrFeNi 2.1 Mo 0.3 alloy exhibits an excellent yield strength of 926 MPa, a fracture strength of 2497 MPa, and a compressive strain of 39.5%. Furthermore, it displays superior corrosion resistance, characterized by a high pitting potential of +282 mV and a low passive current density. Advanced characterization techniques reveal that the in situ formation of composite oxide phases, including MoO 2 , MoO 3 and Cr 2 O 3 significantly enhances the stability and barrier properties of the passive film on the AlCoCrFeNi 2.1 Mo 0.3 alloy. This finding overcomes the conventional trade-off between strength and corrosion resistance in traditional alloy design and establishes a novel design principle for developing high-performance corrosion-resistant alloys, particularly for use in harsh chloride-containing environments.