DISTINCTIVE STRUCTURAL FEATURES OF ND-FE-AL AMORPHOUS ALLOY SYSTEM

Amorphous alloys are formed by melt-spinning over an extremely wide co mposition range in the ternary Nd-Fe-Al system. Accordingly, three Nd- based Nd65Fe25Al10, Fe-based Nd20Fe70Al10 and Al-based Nd10Fe5Al85 amo rphous alloys, and Nd30Fe40Al30 amorphous alloy containing nearly equa l contents of each element, were prepared. Their local atomic structur es have been determined by x-ray diffraction. This reveals some distin ctive structural features in each composition range. An Fe-rich region exists in the Nd-based alloy and a Nd-rich region in the Fe-based all oy. On the other hand, the prepeak in the Al-based alloy indicates the presence of chemical short range order. This is also confirmed by the fact that the interatomic distances for the nearest neighboring pairs are shorter than those evaluated by the atomic radii. In Nd30Fe40Al30 alloy, it seems that the local atomic structure may be a mixture of t hose in the other three alloys.