Abstract
Crystallization from a melt and from a metallic glass both occur in an undercooled liquid. In this way identical nucleation mechanisms can operate in the two cases. However, in metallic glasses, unlike conventional solidification at low undercooling, the low atomic mobility permits the resolution and microscopical study of nucleation processes on added particles. Conventional aluminium grain-refiner based on Al-Ti-B has been used to obtain nucleant particles embedded in a glassy matrix of Al85Y8Ni5Co2 (at%). During crystallization from the glassy state, nucleation and growth of α-Al can be observed on TiB2 particles coated with a layer of Al3Ti Empirical relations found in casting practice of Al-alloys, such as excess Ti necessary for grain refinement, can be related to the observed nucleation mechanism, which is found to be very sensitive to both crystallographic and chemical factors.
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Schumacher, P., Greer, A.L. (2016). Studies of the Action of Grain-Refining Particles in Aluminium Alloys. In: Grandfield, J.F., Eskin, D.G. (eds) Essential Readings in Light Metals. Springer, Cham. https://doi.org/10.1007/978-3-319-48228-6_44
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DOI: https://doi.org/10.1007/978-3-319-48228-6_44
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