Microstructural evolution in directional solidification of Nb-doped Co-Sn/Ni–Sn eutectic alloys

被引：0

作者：

Kang, Jilong ^{[1
,2
]}

Li, Jinfu ^{[1
]}

机构：

[1] State Key Laboratory of Metal Matrix Composites and Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai,200240, China

[2] School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou,730070, China

来源：

Applied Physics A: Materials Science and Processing | 2021年 / 127卷 / 11期

基金：

中国国家自然科学基金;

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摘要：

(Co76Sn24)99.5Nb0.5 and (Ni81.3Sn18.7)99.5Nb0.5 eutectic alloys were directionally solidified and the microstructural evolutions were investigated. Addition of minor Nb to the eutectic alloys destabilized the eutectic solidification interface. The (Co76Sn24)99.5Nb0.5 eutectic interface changed from planar to cellular, to dendritic and then to seaweed morphology with increasing withdrawal velocity at temperature gradient of 200 K/cm. At larger temperature gradient of 300 K/cm, however, dendritic growth did not occur. The cellular interface directly transited into seaweed pattern. In contrast, the (Ni81.3Sn18.7)99.5Nb0.5 eutectic interface with relatively larger interfacial energy anisotropy tended to grow in dendritic pattern. Compared with single β-Co3Sn2 phase, the α-Co/β-Co3Sn2 lamellar eutectic is conducive to growing into seaweed morphology. The critical growth velocity for transition from planar to cellular interface was calculated and the mechanism underlying the interface morphology selection was analyzed. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.

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