Estimation of thermodynamic properties of Cu–La binary alloy with modified Miedema’s theory


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According to modified Miedema’s theory, mixing enthalpies (ΔH), excess entropies (SE), excess Gibbs free energy (GE), and component activities (a) of Cu–La binary alloy were estimated using the basic thermodynamic principles and some simple physical parameters of Cu and La, such as electronegativity, atomic volume and electron density. Based on the Cu–La binary alloy phase diagram, the Gibbs free energy of the phase precipitation reactions of Cu6La and Cu5La was deduced. The results showed that the values of ΔH, SE, and GE of Cu–La binary alloy were all negative. Compared to the ideal solution, the activities of the components presented a large negative deviation from Raoult’s law, which indicated that there was a strong interaction between Cu and La. The calculated data are well consistent with the experimental data. The Gibbs free energies of the phase precipitation reactions of Cu6La are lower than those for Cu5La, which means that Cu6La is thermodynamically more stable than Cu5La. Furthermore, the experimental results show that rareearth rich Cu6La phase particles in copper matrix are formed after La microalloying.

Sobre autores

Hai-hong Li

School of Environment and Materials Engineering; Institute of Metal Research

Email: shzhang@imr.ac.cn
República Popular da China, Yantai, 264005; Shenyang, 110016

Shi-hong Zhang

Institute of Metal Research

Autor responsável pela correspondência
Email: shzhang@imr.ac.cn
República Popular da China, Shenyang, 110016

Yan Chen

Institute of Metal Research

Email: shzhang@imr.ac.cn
República Popular da China, Shenyang, 110016

Ming Cheng

Institute of Metal Research

Email: shzhang@imr.ac.cn
República Popular da China, Shenyang, 110016

Hong-wu Song

Institute of Metal Research

Email: shzhang@imr.ac.cn
República Popular da China, Shenyang, 110016

Jin-song Liu

Institute of Metal Research

Email: shzhang@imr.ac.cn
República Popular da China, Shenyang, 110016

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