Comparative Estudy of High Entropy Alloys MoNbTaTiZr and FeMoTaTiZr

Abstract

High-entropy alloys (HEAs) are a class of materials that have gained significant attention in recent years due to their unique properties and potential applications in various industries. One such promising HEA is the MoNbTaTizr high-entropy alloy, which displays excellent corrosion resistance and biocompatibility alongside good mechanical properties. Mo-Nb-Ta-Ti-Zr system, with low bio-toxicity for the human body, is currently being testeр both for the manufacture of surgical instruments and for orthopaedic applications. Another promising highentropy alloy that has attracted researchers for its potential applications in various fields is FeMoTaTiZr. Exchanging one of the elements may result in important variation of properties of a material. This work studies two different samples of high-entropy alloys MoNbTaTizr (named NbHEA) and FeMoTaTiZr (named FeHEA), both produced at laboratory scale in an electric-arc remelting equipment, keeping similar atomic percentage of the elements in both alloys. Optical microscopy, scanning electron microscopy and energy dispersive x-ray spectroscopy (EDX) techniques were used to characterize the microstructure of the alloys (see Fig.1), showing the difference in composition inside the dendrite zones and the interdendrite areas. Replacing Nb for Fe has a strong influence in the Mo presence inside the dendrite. The corrosion properties of the synthesized alloys were evaluated under simulated biological environment using potentiodynamic polarization method and electrochemical impedance spectroscopy (EIS). FeHEA has a smaller corrosion rate in simulated body fluid than NbHEA but is more susceptible to pitting corrosion than this.