Formation and Crystallization Kinetics of Amorphous Alloys

Abstract

Metallic glasses have a combination of amorphous structure and metallic bond providing them a new and unique quality, which cannot be found either in pure metals or in crystal alloys. From the technological point of view, transition metals have attracted much attention during the last decades due to their very interesting properties. Thin films of this kind of material have been made amorphous over a broad composition range by several methods. The amorphisation is achieved by the incorporation of a group VIIIA element during the deposition process. There are many factors working on the elements effecting the chemical reaction in forming binary compound in solution. The amorphous formation mechanism deposition was studied from the viewpoint of the forming thermodynamics, kinetics, and crystallography of amorphous alloys. The experimental results showed that the ilk atoms with chemical bonds energy from a high capability of forming into compounds than that of congener atoms. The crystal kinetics showed that the stable phase of amorphous structures would arrive by using its superfluous energy when there were enough nuclei. Based on the analyses, it was proposed that the banded structure was induced by the variation of active atoms with a proper thickness, which was alternated depletion and enrichment of anions in the diffusion layer due to generation and evolution of hydrogen gas. The chemical force plays an important part in the formed alloys, the factors working on chemical reaction effect on the formed alloys in the same. A number of steady motes are in a high speed velocity, and collide with each other in all probability. Stability is an important factor related to crystallization, which is generally a thermally activated process of transition from a disordered amorphous structure to an ordered crystal structure. Study of kinetics of crystallization provides Ec, the activation energy of crystallization and parameters like Avrami exponent n, responsible for the mechanism of crystallization. This helps to determine the thermal stability of the amorphous. The deposited in solution not only have the single element characteristics but their mixed characteristics, and appear better properties than each of them. The amorphous alloys have many better mechanical properties, such as high rigidity, better toughness, corrosion resistance and so on, and special properties, as the optics properties, the magnetic properties, the electric properties and so on. So these amorphous alloys aroused many investigators to study on their special properties so that they can play their important roles in modern society, especially in the industry, agriculture, energy sources, materials fields and biologically.