Crystallization kinetics in Fe−B−Si metallic glasses

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Abstract
Crystallization kinetics of Fe-B-Si metallic glasses, as characterized by the effective activation energy Ec and the Avrami exponent n have been studied using Differential Scanning Calorimetry. The data show that in the hypoeutectic (Fe-rich) region, the glasses crystallize into α-(Fe,Si) and Fe3B in that order. The growth of crystallites is diffusion controlled, and Ec falls off rapidly away from the eutectic trough. In the hypereutectic region, both crystalline phases are obtained simultaneously. Thermal stability is greatly enhanced by addition of Si(∼3 at. %) and the growth process is no longer purely diffusion controlled. The behavior of Ec and n versus composition is discussed. Effects on Ec and n of additions of small amounts of Ni and Mo are also reported. Such additions have direct relevance to the design of new glasses for applications at high frequencies.