Comparative Studies of Cr/Ti Additions for Cu40Mn25Al20Fe5Ni5 HEA on Microstructure and Corrosion Behavior in HNO3 Solution

The influence of Cr or Ti additions to Cu 40 Mn 25 Al 20 Fe 5 Ni 5 high entropy alloy (HEA) on the microstructure and corrosion behavior in different concentrations of HNO 3 solution were investigated. The microstructures of the Cu-rich HEAs are characterized and analyzed. Microstructural analysis of the HEAs indicates the formation of a dendritic structure. Also, the phases are identified by using X-ray diffraction (XRD). The corrosion behavior of the investigated HEAs in the HNO 3 solution was studied. The corrosion rate (CR) for Cu 40 Mn 25 Al 20 Fe 5 Ni 5 Ti 5 HEA (Ti 5 HEA) has a lower value than Cu 40 Mn 25 Al 20 Fe 5 Ni 5 Cr 5 HEA (Cr 5 HEA). The morphology of the corroded HEAs was investigated by using SEM images, EDX analysis, and mapping for elemental distribution. Cr addition led to the formation of a Cr 2 O 3 protective film on the dendrites. However, the Ti 5 HEA has a good surface morphology with a homogenous distribution than Cr 5 HEA which is associated with a decrease in the corrosion rate.