Effects of minor B addition on microstructure and properties of Al19Co20Fe20Ni41 eutectic high-entropy alloy

The simultaneous strengthening of mechanical and magnetic properties is an ideal fabrication strategy for soft-magnetic materials. A non-equiatomic Al19Co20Fe20Ni41 eutectic high-entropy alloy was prepared to investigate the alloying effect of B on the microstructure evolution, phase formation, mechanical and soft-magnetic properties. With the increase in B content, the microstructures of (Al19Co20Fe20Ni41)100−xBx alloys transformed from the initial lamellar eutectic structure (x=0) to the divorced eutectic structure (x>0.6). Fine borides precipitated in the intergranular phase (x≥0.6). The hardness of alloys increased from HV 328.66 to HV 436.34 and the compression mechanical performance displayed a transition from plastic material to brittle material. The Al19Co20Fe20Ni41 alloy possesses good soft-magnetic properties, and the minor B addition has little effect on it. Increasing the resistivity can effectively reduce the eddy current loss when used as a soft-magnetic material.