Transitional and refractory elements-based high entropy alloy developed through mechanical alloying and microwave sintering: Tribological and corrosion responses

Abstract

Over the last decade, High Entropy Alloys (HEAs) gained recognition in various sectors (nuclear, aerospace, marine, and biomedical) due to their excellent strength, thermal stability, biocompatibility, wear and corrosion characteristics. This study deals with the development of a novel HEA through a microwave-assisted powder metallurgy, which is an economical approach and overcome the limitations of conventional fabrication techniques. A series of multi-principal alloys are developed, and noted that the HEA is developed through 15 h of ball milling of metallic powders followed by compaction and microwave sintering at 1400 °C at controlled heating and cooling rates. Thus, developed alloys were further examined to record their mechanical properties, tribological, and corrosion responses. The microstructural and metallurgical changes were recorded using Field Emission Scanning Electron Microscopy (FESEM), X-Ray Diffraction (XRD), and X-Ray Photoelectron Spectroscopy (XPS). Finally, the tribological and corrosive responses were recorded using a multifunctional tribometer and a potentiostat (potentiodynamic polarization and electrochemical impedance spectroscopy (EIS)). It is observed that the 1400 °C sintered HEA exhibited superior mechanical, tribological, and corrosive properties. It is worth hypothesizing that the transformation of dual phases (BCC and FCC) to the single BCC phase was responsible for the exceptional properties. Hence, this affordable fabrication approach can be used to develop bulk HEAs to explore other functional characteristics in the future.