Manufacturing ultra-low sulfur and oxygen (FeCrCoMnNi)100-xCx high-entropy alloys using a commercial ferroalloy feedstock via induction melting and slag refining

Commercial ferroalloys, such as high-carbon ferromanganese (HCFeMn), low-carbon ferrochromium (LCFeCr), and ferronickel (FeNi) alloys were chosen as the raw materials for the sustainable manufacturing of FeCrCoMnNi-based high-entropy alloy (HEA) with differing carbon contents due to their cost-effectiveness and the efficiency of the manufacturing process. The carbon content in the HEA prepared by this method originates from the ferroalloys themselves, called self-alloying . The effect of the carbon content on the phase composition, grain size and microhardness of three HEAs were investigated. Therefore, impurity control (desulfurization and deoxidation) during ferroalloy-based melting and refining was systematically investigated for the FeCrCoMnNi HEA with varying carbon contents (0.3, 0.7, and 1.8 at%) using the CaO-Al 2 O 3 -MgO (CAM) ternary slag in an induction melting furnace at 1773 K. The sulfur content in the alloys prepared by this method was less than 6 ppm and the oxygen content less than 13 ppm. The overall mass transfer coefficient of sulfur in the three types of HEA was between2.0×10 -6 m/s and 3.0×10 -6 m/s at 1773 K. The kinetic model of deoxidation of HEA refined by CAM slag was also established, and the mass transfer coefficient of oxygen ( ) ranging from 2.0×10 -7 m/s to 4.0×10 -7 m/s in the different compositions of FeCrCoMnNi- x C HEA at 1773 K, indicating that the oxygen in HEA is more difficult to be removed compared with other metallic systems such as steels, Ni-base alloys, etc. • Novel procedure for manufacturing C-alloyed HEA using commercial ferroalloys feedstock was proposed • Carbon was implemented by self-alloying mechanism using high carbon ferroalloys • Impurity sulfur and oxygen were effectively removed to ∼6 and ∼13 ppm, respectively, by slagging method in an induction melting furnace