Structural relaxation of grain-boundary amorphous layers on nanocrystalline FeSiNbCuB alloy and the oscillating behavior of Young's modulus

Amorphous alloys Fe73.5Cu1Nb3Si13.5B9 prepared by a melt-spinning technique were annealed at a temperature of 500 degrees C for different times. The c hange of the average grain size( d), the volume fraction( V-c) of the alpha -Fe phase and the Young's modulus with the annealing time( t) were investig ated by X-ray diffraction(XRD) and Modulus measurements. The relation of d- t shows that the alpha-Fe phase has the character of staged-growth. The rel ation of Et has an oscillating behavior. The chemical composition of the am orphous layer surrounding the alpha-Fe phase and the balanced chemical comp osition of the grain-boundary amorphous layers were calculated. The time of the composition balanced was calculated by using Fick equation, it had the same scale with the period of the alpha-Fe phase staged-growth. The oscill ating behavior of E-t may come from the staged-growth of alpha-Fe phase con trolled by Nb atom diffusion and the periodical structural relaxation of gr ain-boundary amorphous layers.