Decoupled versus coupled growth dynamics of an irregular eutectic alloy. (December 2020)

• Record Type: Journal Article
• Authors: Mohagheghi, Samira; Bottin-Rousseau, Sabine; Akamatsu, Silvère; Şerefoğlu, Melis
• Is Part Of: Scripta materialia. Number 189(2020)
• Page Start: 11
• Page End: 15
• Publication Date: 2020-12
• Subjects: Irregular eutectic growth -- Directional solidification -- Eutectic solidification -- Interface dynamics -- Solidification microstructures; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2020.07.053
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: We present an experimental study of irregular growth patterns observed in real time during thin-sample directional solidification of a faceted/nonfaceted eutectic alloy, namely, the transparent 2-amino-2-methyl-1, 3-propanediol (AMPD)-succinonitrile (SCN) system. The body-centered cubic SCN crystals are nonfaceted, while monoclinic AMPD crystals grow as faceted needles. At low velocities (<0.3 µms −1 ), a decoupled growth regime is observed, during which the tip of the AMPD crystals grows ahead of the SCN-liquid interface. At intermediate velocities, an unsteady coupled-growth regime takes place, with intermittent pinning of triple SCN-AMPD-liquid junctions, and frequent noncrystallographic branching. At higher velocities (>1 µms −1 ), two-phase fingers form. Graphical abstract: Image, graphical abstract