Impact of growth velocity on grain structure formation during directional solidification of a refined Al-20 wt.%Cu alloy
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Date
2020
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Crystal Growth
Abstract
The paper presents detailed analyses of solidification experiments performed on a refined Al-20 wt.%Cu alloy using the SFINX (Solidification Furnace with IN situ X-radiography) laboratory facility. Directional solidifica tions of a sheet-like sample were carried out in a horizontal configuration, with the main surface of the sample parallel to the ground. The sample was solidified for a wide range of cooling rates to obtain various grain structures, from columnar to elongated and equiaxed. The formation of the grain structure was observed in-situ and in real-time by X-radiography, which allows the dynamic of solidification phenomena to be thoroughly analyzed. Based on the radiographs, quantitative measurements were performed to accurately describe the so lidified grain structure, namely the nucleation position, nucleation rate, grain size, grain elongation factor and growth orientation. The experiments showed that increasing the growth velocity leads to a decrease of both the grain size and grain elongation factor, resulting in a more homogeneous and isotropic grain distribution. The grain characteristic parameters were also sensitive to variations of the temperature gradient in the Field-of-View. The results were discussed by analyzing the impact of the solidification parameters on the constitutionally undercooled liquid zone ahead of the solidification front
Description
Journal of Crystal Growth, Volume 548, 15 October 2020, 125819
https://doi.org/10.1016/j.jcrysgro.2020.125819