Remelting and solidification of a 6082 Al alloy containing submicron yttria particles: 4D experimental study by in situ X-ray microtomography

• Published in: Materials & Design 2015-12, Vol.87, p.313-317
• Main Authors: Daudin, R., Terzi, S., Lhuissier, P., Salvo, L., Boller, E.
• Format: Article
• Language: English
• Subjects: Aluminum base alloys; Chemical Sciences; In situ micro-tomography; Material chemistry; Melting; Nano-composites; Nanocomposites; Pushing; Pushing-engulfment; Remelting; Solidification; Spatial distribution; X-ray microtomography; Yttrium oxide
• ISSN: 0264-1275; 0261-3069; 1873-4197; 0264-1275
• DOI: 10.1016/j.matdes.2015.07.141

The behaviour of submicron Y2O3 particles incorporated in a 6082 alloy was characterized by in situ X-ray microtomography during remelting and solidification. The presence and spatial distribution of the Y2O3 particles in the alloy were revealed through the dissolution of the intermetallic phase upon remelting. They were mostly found agglomerated at grain boundaries suggesting that particle pushing is likely to be the predominant mechanism in interfacial interactions. This trend was then confirmed by the direct observation of the solidification process from the fully molten state showing clusters of yttria particles pushed by growing dendrites. In addition to providing fundamental insights into the solidification of nano-composites, these results also point out potential issues in recycling these materials and the necessity to re-disperse particles after a remelting step. [Display omitted] •In situ X-ray synchrotron tomography to observe in real time the melting and solidification of a Metal Matrix Nanocomposite•The location of Y2O3 particles are revealed by dissolving in the intermetallic phase.•Y2O3 tends to agglomerate in large and branched clusters with a stable morphology above the matrix liquidus.•Y2O3 clusters are pushed by the dendrites growth during solidification.