Entropy-driven phase stability and slow diffusion kinetics in an Al_0.5CoCrCuFeNi high entropy alloy

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• 作者：Chun Ng ; Sheng Guo ; Junhua Luan ; Sanqiang Shi ; C.T. Liu
• 关键词：B. Thermal stability ; C. Thermomechanical treatment ; E. Phase stability ; prediction
• 刊名：Intermetallics
• 出版年：2012
• 出版时间：December, 2012
• 年：2012
• 卷：31
• 期：Complete
• 页码：165-172
• 全文大小：930 K

文摘

Previous work on the stability of the solid solution phases in the high entropy alloys is inconclusive. We used a series of thermo-mechanical treatments to study the stability of the solid solution phases in a high-entropy Al_0.5CoCrCuFeNi alloy. The solid solution phases were found to be stable, against the intermetallic compounds, at high temperatures >850?¡ãC and at low temperatures <300?¡ãC. At intermediate temperatures, however, the intermetallic ¦Ò-phase co-existed with the solid solution phases. The experimental observations were verified by the thermodynamic calculation results. The mechanisms for the phase stability, both at equilibrium and after quenching-equivalent annealing treatments, were discussed, and the roles of high entropy and slow diffusion kinetics were highlighted.