Article ID Journal Published Year Pages File Type
1445615 Acta Materialia 2014 7 Pages PDF
Abstract

In situ synchrotron X-ray radiography of columnar dendritic growth in Al–15 wt.% Cu–9 wt.% Si–0.015 wt.% Sr alloy has been carried out with the temporal and spatial resolutions of 100 ms and 0.65 μm, respectively. Two-dimensional (2-D) projected images have been processed and analysed to retrieve three-dimensional (3-D) spatial information on the growing dendrite network, through X-ray transmission contrast differences that account for solute-composition variations in the liquid and thickness variations in the growing dendrites. The analysis elucidates the way in which gravity-driven natural convection and solute sedimentation can result in solid fractions that deviate markedly from Scheil and Lever-rule-based models, which could alter mushy zone permeability. Furthermore, the ability to render 3-D spatial details may lead to future opportunities to use 2-D radiography in the development and validation of more sophisticated 3-D models of dendritic growth.

Related Topics
Physical Sciences and Engineering Materials Science Ceramics and Composites
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