Nano-Crystallization and Stability of an Amorphous Phase in Fe-Nd-B Alloy under 2.0 MeV Electron Irradiation

摘要

Formation of nano-structure in melt-spun ternary Fe-Nd-B alloys was examined focusing on electron irradiation induced crystallization. In Fe_(82.2)Nd_(7.1)B_(10.7) (Fe/Nd/B = 23/2/3), Fe_(77)Nd_(4.5)B_(18.5) and Fe_(71)Nd_9B_(90) alloys, melt-spun amorphous phase changed to a crystalline phase during electron irradiation and nano-structure was formed. The crystalline phase in melt-spun Fe_(86)Nd_9B_5 and Fe_(82.4)Nd_(11.8)B_(5.8) (Fe/Nd/B = 14/ 2/1) alloys was unstable under electron irradiation and electron irradiation induced amorphization occurred. With the further irradiation, crystallization from the amorphous phase was induced resulting in forming nano-crystalline structure. The onset total dose for the irradiation induced crystallization, namely, stability of the amorphous phase against electron irradiation depends strongly on the Fe-ratio, crystallization temperature, mismatch entropy and mixing enthalpy of the alloys.