High entropy alloys (HEAs) consisting of five or more principle elements are known as an emerging novel material because of superior properties resulting from the alloy effects of mixing elements. Several HEAs systems have been developed by adjusting the compositions. Among them, an equiatomic Fe-Cr-Ni-Co-Mn alloy (also known as the Cantor alloy) is a single FCC structure and has good resistance against brittleness at low temperatures. Several HEAs studies have detailed the microstructure, processing, and related mechanical properties. However, the materials scales only limit in the laboratory. The knowledge of microstructure and corrosion resistance of the Fe-Cr-Ni-Co-Mn alloy for industry application scales is still absent nowadays.

In this study, a 50-kg-bulk Fe-Cr-Ni-Co-Mn alloy was melted and casted. The alloy was homogenized, forged, and rolled. The as-cast bulk and deformed bulk alloys had different microstructures. The as-cast ingot with a diameter of approximately 120 mm was sliced using wire electrical discharge machining. The as-cut disk showed brown color on the rim of the disk and dark len-shaped in the middle. The XRD results showed different patterns from the distinct regions. The microstructure and the related corrosion properties of the specific was compared. The effect of segregation of the as-cast bulk was re-constructed with the related corrosion resistance. The in-situ corrosion observation system was also built and employed to study the corrosion behavior of the Fe-Cr-Ni-Co-Mn alloy in comparison to 316 stainless steel.

Key Words: high-entropy alloys, Fe-Cr-Ni-Co-Mn alloys, corrosion, segregation, as-casted