LAUSR

Abstract Al-Ni-Co alloy has been widely applied in various industrial fields due to its excellent thermal and magnetic stability. In this paper, new Al-Ni-Co ribbons are prepared by simple processes combining melt-spinning with annealing, and their phase transition, microstructure and magnetic properties are studied. The results show that after as-spun ribbons are annealed, the grain size of ribbons increases from 1.1 ± 0.3 μm to 4.8 ± 0.8 μm, but still much smaller than that of the bulk Al-Ni-Co alloy manufactured by traditional technologies. In addition, some rod-like Al 70 Co 20 Ni 10 -type, Al 9 Co 2 -type and Fe 2 Nb-type phases are precipitated at grain boundaries; simultaneously, the distinct spinodal decomposition microstructure with periodic ingredient variation is thoroughly formed in all grains by the reaction of α → α 1  + α 2 . Furthermore, the α 1 and α 2 distribute alternately like a maze, the Fe-Co-rich α 1 phase holds 35.9–47.3 vol%, while the Al-Ni-rich α 2 phase occupies the rest. Finally, the coercivity of annealed ribbons can reach to 485.3 ± 76.6 Oe. If the annealed ribbons are further aged at 560 °C, their H c even increases to 738.1 ± 81.0 Oe. The coercivity mechanism is discussed by the combination of microstructure and domain structure.