Design and microstructure analysis of globules in Al-Co-La-Pb immiscible alloys with an amorphous phase

Publication date: 5 March 2017
Source:Materials & Design, Volume 117
Author(s): Takeshi Nagase, Mamoru Takemura, Mitsuaki Matsumuro, Megumi Matsumoto, Yoshikazu Fujii
An immiscible alloy with an amorphous phase, Al-Co-La-Pb, was designed by the combination of empirical rules, prediction of phase diagrams based on ab initio calculations, and thermodynamic calculations. The solidification microstructure of rapidly solidified Al-Co-La-Pb melt-spun ribbons was investigated. Liquid-phase separation and the formation of an amorphous phase occurred simultaneously in the Al-Co-La-Pb alloy, resulting in the formation of Pb globules embedded in the Al-Co-La–based amorphous matrix. The particle size distribution of the globules and the formation of Pb nanoglobules were explained by the multistep liquid-phase separation. STEM observation clarified the microstructure of oxygen-enriched globules with double shell layers in the Al-Co-La-Pb alloy.

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