Progress of solid-state reaction and class formation in mechanically alloyed Zr65Al7.5Cu17.5Ni10

The progress of amorphization in mechanically alloyed Zr65Al7.5Cu17.5Ni10 p owder was investigated in detail using x-ray diffraction, Rietveld analysis , magnetic measurements, metallography, as well as scanning and transmissio n electron microscopy. For this purpose mixtures of elemental powders were used as starting materials and milled for distinct periods of time. Deraile d investigations of the microstructural evolution during milling indicate t hat the amorphization proceeds by solid-state reaction, similar to what is known fur mechanical alloying of binary alloy systems and other multicompon ent alloys. A layered structure typical for mechanically alloyed material a rises in the early stages. Alloying of the lamellae, which consist of pure elements, proceeds to some extent via anomalous fast diffusion of small-siz ed atoms. Besides this, the larger atoms also contribute to alloying. The o bserved reaction paths are compared with well-known models describing the a morphization by solid-state reaction in binary systems, suggesting that dis location pipe diffusion plays a decisive role for intermixing the elements and promoting amorphization. (C) 2000 Acm Metallurgica Inc. Published by El sevier Science Ltd. All rights reserved.