Microstructure and properties of Al_0.3CrFe_1.5MnNi_0.5Ti _x and Al_0.3CrFe_1.5MnNi_0.5Si _x high-entropy alloys

In this article, the microstructure, hardness, and corrosion resistance of the Al_0.3CrFe_1.5MnNi_0.5Ti _x and Al_0.3CrFe_1.5MnNi_0.5Si _x (x = 0, 0.2, 0.5, 1.0) high-entropy alloys were investigated via X-ray diffraction (XRD), scanning electron microscopy (SEM), digital display Vickers hardness tester, and electrochemical technique. These alloys are mainly composed of BCC solid-solution structure. When adding high content of Ti or Si element (x ≥ 0.5), some intermetallic compounds are found in the microstructure, which makes the alloys have a high hardness, high brittleness, and easy cracking. While the alloys with low content of Ti or Si (x = 0.2) have a hardness of HV 420–HV 430, and its hardness increases about 14 % compared with that of Al_0.3CrFe_1.5MnNi_0.5. Electrochemical results in 3.5 % NaCl solution show that the alloying elements Ti and Si have a negative influence on the corrosion resistance of the Al_0.3CrFe_1.5MnNi_0.5 alloys.