(1. 鄭州大學 材料工程學院， 鄭州 450002;
2. 河南大學 特種功能材料重點實驗室， 開封 475001;
3. 武漢大學 物理系， 武漢 430072;
4. 北京有色金屬研究總院， 北京 100088)
摘 要: 采用XRD， SEM和TEM等方法， 研究了鑄態(tài) Al58.8Cu36.6Fe3.5Si1.1合金（973K保溫2.5h后水淬）的顯微組織及相組成。 觀察到鑄態(tài)樣品中存在4種不同的相， 即初生準晶I相、 Φ相、 θ-Al2Cu相 和η-AlCu相。 對準晶I相及其晶體近似相R相， 提出相應的自由能計算模型及算法， 從理論上說明準晶（Al61.89Cu25.61Fe11.10）I相是高溫穩(wěn)定相， 當溫度低于938K時， 將形成其晶體近似相R相。
關鍵字: 熱力學； 凝固組織； 初生準晶相； 自由能
of primary Al-Cu-Fe icosahedral quasicrystal phase
QU Wen-bang3, SUN Li-hong4
（ 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
