Al

0.8

CrFe

2

Ni

x

high-entropy alloys（x denotes the atomic content of Ni element when the atomic content of Al

Cr and Fe is 0.8

1 and 2

respectively） were prepared by vacuum arc melting. The effects of Ni content on microstructures and mechanical properties of the alloy were investigated by using optical microscope

X-ray diffraction（XRD）

micro-hardness testing and compression testing. The results show that the alloy with dendritic+cellular crystal morphology has a B

2

+BCC crystal structure when x=0.50. When x=1.25

the crystal structure is transformed to single BCC with a single dendritic morphology. When x=2.00

the crystal structure is changed into a mixed structure of FCC+BCC with a dense lamellar eutectic-like morphology. With the further increase of Ni content

the alloy maintains FCC+BCC structure when x=2.75. However

the proportion of FCC phase is dramatically increased and complete dendritic morphology appears. The hardness of Al

0.8

CrFe

2

Ni

x

high entropy alloys is decreased with the increase of x. Meanwhile

the yield strength is decreased and the strain is increased.