Atomic Transport and Relaxation in Rapidly Solidified Alloys

Abstract

Diffusion processes in solids play a central role in tailoring high-quality materials for technical applications. Whereas in crystalline solids a number of intrinsic self-diffusion processes could be identified previously, it is just recently that the situation in amorphous materials could be clarified. In crystalline solids self-diffusion may be controlled by vacancies in thermal equilibrium (noble metals, transition and refractory metals) [4.1, 2], by self-interstitial atoms as in Si [4.3], or by direct atomic exchange and by ring mechanisms as discussed recently for alkaline metals and some transition metals [4.2, 4]. None of these mechanisms seems to apply directly to amorphous alloys. Diffusion in amorphous alloys has been reviewed by several authors concentrating on different aspects. Cahn [4.5], Egami [4.6], and Egami and Waseda [4.7]considered the relations between diffusional properties and the glass-forming ability. Johnson [4.8]considered the relations between diffusion and diffusion-controlled amorphization processes. Cantor [4.9]emphasized that the diffusivity of metals and metalloids in glasses scales with the glass transition temperature. Taub and Spaepen [4.10]studied the relations between viscosity and diffusional properties, Kronmüller and co-workers [4.11–13]as well as Faupel et al. [4.14]concentrated on the self-diffusion of metallic components and magnetic and mechanical relaxation phenomena.KeywordsInternal FrictionAmorphous AlloyArrhenius PlotActivation EnthalpyDiffusion ProfileThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.