Eutectic-to-metallic glass transition in the Al–Sm system
Eutectic-to-metallic glass transition in the Al–Sm system
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DOI：
10.1016/j.actamat.2011.07.015
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发表时间：
2011-10
期刊：
影响因子：
9.4
通讯作者：
N. Wang;Y. E. Kalay;R. Trivedi
中科院分区：
文献类型：
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作者：
N. Wang;Y. E. Kalay;R. Trivedi
采用Bridgman技术、激光技术和熔体旋压技术相结合的方法，对Al-Sm系界面在很宽的过冷度范围内的微观组织选择进行了系统的实验研究，以增加界面过冷度。低过冷度时形成共晶组织，过冷度过大时形成金属非晶组织。实验的目的是在共晶的生长过程中，随着界面过冷度的增加，从共晶到玻璃的急剧转变。对相变过程中的共晶间距进行了表征，并用考虑界面非平衡效应的共晶生长模型对结果进行了分析。结果表明，玻璃形成所需的界面过冷度很大，这是由于扩散系数的急剧减小或液体粘度的急剧增加与该体系的过冷度和共晶组织中化合物-液界面处附着动力学所需的过冷度的综合作用所致。
A systematic experimental study is carried out to investigate microstructure selection over a very wide range of undercooling at the interface in the Al–Sm system by using a combination of the Bridgman, laser and melt spinning techniques, which give increasing interface undercooling. Eutectic microstructure forms at low undercooling, while metallic glass forms at very large undercooling. Experiments are designed to obtain a sharp transition from the eutectic to glass during the growth of eutectic as the interface undercooling increases with growth. The eutectic spacing at the transition is characterized, and the results are analyzed by using a model of eutectic growth that incorporates non-equilibrium effects at the interface. It is shown that a very large undercooling at the interface, required for glass formation, is obtained due to the combined effects of the sharp decrease in the diffusion coefficient, or the sharp increase in viscosity of the liquid, with undercooling in this system and the large undercooling required for the attachment kinetics at the compound–liquid interface in the eutectic structure.