Effect of Mn content on microstructure and properties of AlCrCuFeMnx high-entropy alloy

AlCrCuFeMnx (x=0, 0.5, 1, 1.5, and 2) high-entropy alloys were prepared using the vacuum arc melting technology. The microstructure and mechanical properties of AlCrCuFeMnx were analyzed and tested by XRD, SEM, TEM, nanoindentation, and electronic universal testing. The results indicate that the AlCrCuFeMnx high-entropy alloy exhibits a dendritic structure, consisting of dendrites with a BCC structure, interdendrite regions with an FCC structure, and precipitates with an ordered BCC structure that form within the dendrite. Manganese (Mn) has a strong affinity for dendritic, interdendritic, and precipitate structures, allowing it to easily enter these areas. With an increase in Mn content, the size of the precipitated nanoparticles in the dendritic region initially increases and then decreases. Similarly, the area fraction initially decreases and then increases. Additionally, the alloy's strength and wear resistance decrease, while its plasticity increases. The AlCrCuFeMn1.5 alloy boasts excellent mechanical properties, including a hardness of 360 HV and a wear rate of 2.4x10(-5) mm(3) <middle dot>N-1<middle dot>mm(-1). It also exhibits impressive yield strength, compressive strength, and deformation rates of 960 MPa, 1,700 MPa, and 27.5%, respectively.