Study on a new high-entropy alloy Nd20Pr20La20Fe20Co10Al10 with hard magnetic properties

Abstract

High-entropy alloys (HEAs) are a new class of alloys that consist of at least five major elements in equimolar or near-equimolar ratios with atomic concentration between 5% and 35%. Many HEAs containing the ferromagnetic elements Fe, Co and Ni show soft magnetic properties, while few HEAs present hard magnetic properties. In this paper, we design and prepare the Nd20Pr20La20Fe20Co10Al10 HEA with hard magnetic property. The magnetic property and microstructure of this alloy have been investigated. The intrinsic coercivity (Hcj), saturation magnetization (Ms), and remanence (Mr) of Nd20Pr20La20Fe20Co10Al10 alloy is 280.0 kA/m, 14.0 Am2/kg and 8.9 Am2/kg, respectively, which is slightly lower than 301.0 kA/m, 14.9 Am2/kg and 9.6 Am2/kg of Nd60Fe20Co10Al10 bulk amorphous alloy. The elasticity modulus (Er) of Nd20Pr20La20Fe20Co10Al10 alloy is 58.7 GPa, 4.6% higher than that of Nd60Fe20Co10Al10 alloy. SEM results show that there are two kinds of amorphous phases with different chemical compositions. TEM results show that Nd (Pr) and La nanocrystals are embedded in the amorphous matrix. The high coercivity of the alloy may originate from the combined effect of exchange coupling and domain wall pinning. Our findings provide a new idea to design HEAs with hard magnetic property leading to widen their applications.