Effect of boron on mechanical and anti-corrosion properties of Al0.3CoFeMnNi high-entropy alloys

A series of Al0.3CoFeMnNiBx high-entropy alloys (x = 0-0.5 in molar ratio) were prepared by vacuum arc melting method. The as-cast Al0.3CoFeMnNi alloy possesses face-centered cubic crystal structure. With boron addition, interdendritic borides are formed. The volume fraction and size of the borides increase with the enhancement of the boron content. The hardness dramatically rises from 4.04 GPa to 8.06 GPa with improving x from 0 to 0.5. The maximum yield strength and compressive strength were found to be 1050 and 1710 MPa, respectively, when x is 0.4. The compressive strain continuously decreases from 37.0% to 24.9% as x increasing from 0.2 to 0.5. The corrosion resistance gradually degrades with increasing the boron content.