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

Abstract

The influence of Cr or Ti additions to Cu40Mn25Al20Fe5Ni5 high entropy alloy (HEA) on the microstructure and corrosion behavior in different concentrations of HNO3 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 HNO3 solution was studied. The corrosion rate (CR) for Cu40Mn25Al20Fe5Ni5Ti5 HEA (Ti5 HEA) has a lower value than Cu40Mn25Al20Fe5Ni5Cr5 HEA (Cr5 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 Cr2O3 protective film on the dendrites. However, the Ti5 HEA has a good surface morphology with a homogenous distribution than Cr5 HEA which is associated with a decrease in the corrosion rate.