Abstract:The effects of Zr on crystallization kinetics of Pr-Fe-B amorphous alloys have been investigated by DTA and XRD methods. It was found that for Pr₈Fe_86-xZr_xB₆(x=0, 1, 2) amorphous alloys, the final crystallized mixture is α-Fe and Pr₂Fe₁₄B, and the metastable Pr₂Fe₂₃B₃ phase occurs during crystallization of Pr₈Fe₈₆B₆ amorphous alloy, not during crystallization of Pr₈Fe_86-xZr_xB₆(x=1, 2) amorphous alloys. By analyzing the activation energy of crystallization, the formation of an α-Fe/Pr₂Fe₁₄B composite microstructure with a coarse grain size in annealed Pr₈Fe₈₆B₆ alloy, is attributed to a difficult nucleation and an easy growth for both the α-Fe and Pr₂Fe₁₄B in the alloy. The addition of Zr can be used to change the crystallization behavior of the α-Fe phase in Pr-Fe-B amorphous alloy, which is helpful to reduce the grain size for the α-Fe phase.

Key words: Pr-Fe-B amorphous alloys; Zr; crystallization kinetics; activation energy