Effect of melt-spinning speed on the microstructure and magnetic properties of Al-Cu-Fe alloy-doped SmCo5 ribbons

Multielement alloy doping is the feature of this paper, and disclosing the relationship between non-equilibrium microstructure and magnetic properties after rapid cooling is the key point. 3 wt% eutectic Al82.8Cu17Fe0.2 alloy was doped into SmCo5 alloy, followed by melt-spinning at 10-40 m/s. It is found all ribbons are composed of Sm(Co, M)(5) and Sm-2(Co, M)(7) phases, but non-equilibrium solidification at different cooling rates results in different distribution characteristics of phases and magnetic properties of the ribbons. The 10 m/s ribbons are composed of Sm-Cu- and Co-rich Sm(Co, M)(5) phases and then the lamellate Sm-2(Co, M)(7) coexists with CeCo5-type Sm(Co, M)(5) grains in the 25 m/s ribbons, while the 40 m/s ribbons form a cellular microstructure with Sm-2(Co, M)(7) grain boundaries and Sm(Co, M)(5) intracellular grains. Correspondingly, the coercivity, remanence, and maximum magnetization of 40 m/s ribbons are 74.3%, 64.3%, and 53.2% higher than those of 10 m/s ribbons. At the same time, the coercivity mechanism and microstructure evolution are discussed.