Coexistence of rod-like and lamellar eutectic growth patterns

• Published in: Scripta materialia Vol. 207; p. 114314
• Main Authors: Bottin-Rousseau, Sabine, Witusiewicz, Victor T., Hecht, Ulrike, Fernandez, Jose, Laveron-Simavilla, Ana, Akamatsu, Silvère
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.01.2022; Elsevier
• Subjects: Condensed Matter; Directional solidification; Eutectic growth; In situ experimentation; Materials Science; Microgravity; Nonlinear Sciences; Pattern Formation and Solitons; Physics; Eutectic growth; Directional solidification; Microgravity; In situ experimentation; microgravity; in situ experimentation; directional solidification
• ISSN: 1359-6462; 1872-8456
• DOI: 10.1016/j.scriptamat.2021.114314

We present the first observations of a large-scale coexistence between rod-like and lamellar eutectic growth patterns during directional solidification of a eutectic alloy. In situ experiments with real-time optical monitoring were carried out under microgravity onboard the International Space Station (ISS). We used the transparent succinonitrile-d,camphor eutectic alloy that ordinarily forms rod-like patterns. At low growth velocity, short lamellae stabilized at the contact line with a sample glass wall. In the presence of a controlled transverse temperature gradient, the coupled-growth pattern experienced a global drift along an inclined isotherm, and a stable lamellar domain spread over the solidification front. The propagative nature of the lamellar-to-rod transition was evidenced. The advance of the lamellar/rod domain boundary was determined by a slowly amplifying varicose instability of the lamellae. On a large scale, the domain boundary underwent a dynamic faceting. [Display omitted]