(1. 郑州大学 材料工程学院， 郑州 450002;
2. 河南大学 特种功能材料重点实验室， 开封 475001;
3. 武汉大学 物理系， 武汉 430072;
4. 北京有色金属研究总院， 北京 100088)
摘 要: 采用XRD， SEM和TEM等方法， 研究了铸态 Al58.8Cu36.6Fe3.5Si1.1合金（973K保温2.5h后水淬）的显微组织及相组成。 观察到铸态样品中存在4种不同的相， 即初生准晶I相、 Φ相、 θ-Al2Cu相 和η-AlCu相。 对准晶I相及其晶体近似相R相， 提出相应的自由能计算模型及算法， 从理论上说明准晶（Al61.89Cu25.61Fe11.10）I相是高温稳定相， 当温度低于938K时， 将形成其晶体近似相R相。
关键字: 热力学； 凝固组织； 初生准晶相； 自由能
of primary Al-Cu-Fe icosahedral quasicrystal phase
（ 1. Materials Engineering College,
Zhengzhou University, Zhengzhou 450002, China;
2. Laboratory of Special Functional Materials,
Henan University,Kaifeng 475001, China;
3. Department of Physics, Wuhan University,
Wuhan 430072, China;
4. General Research Institute for Nonferrous Metals,
Beijing 100088, China）
Abstract: The microstructures and constituent phases of the Al58.8-Cu36.6Fe3.5Si1.1 alloy, water quenched after retaining 2.5h at 973K, were examined by means of optical metallography , scanning electron microscopy, transmission electron microscopy and X-ray diffraction analyses. The investigation reveals that the constituent phases of the Al58.8Cu36.6Fe3.5Si1.1 alloy are the I phase, Φ phase, η(AlCu) phase and θ(Al2Cu) phase. A thermodynamic model and the calculation method of the change of Gibbs free energy during the primary solidification for the icosahedral quasicrystal phase and its approximant crystal phase are proposed. The thermodynamic analyses show that the icosahedral quasicrystal phase solidifies as a primary stable phase when temperature is higher than 938K. Below 938K, its approximant crystal phase emerges.
Key words: thermodynamic analyses; solidification structure; primary quasicrystal phase; gibbs free energy
