(北京工業(yè)大學 固體微結構與性能研究所，北京 100124)
摘 要: 應用掃描電鏡和透射電子顯微方法分析Al75Pd15Fe10鑄態(tài)合金凝固組織中復雜合金相的分布、成分以及微觀結構特征。針對凝固過程中形成的兩種復雜合金相，對比分析其中原子團排布的局部及長程特征，并對其形成條件進行討論。結果表明：凝固組織中同時存在兩種經(jīng)歷不同相變過程而形成的、但含有以同類柱狀(1.6 nm周期)原子團為基本結構單元的復雜合金相，它們分別屬于具有高密度缺陷的十面體準晶和相關近似晶體相(ε16)。與ε16結構相比，準周期結構的形成溫度區(qū)間相對較高；在Al-Pd-Fe復雜合金相結構形成的成分范圍內(nèi)，Pd含量的增加和凝固速度的降低有利于原子團的充分形成，也有利于原子團分布密度的增大以及長程排列周期性的建立。
關鍵字: Al-Pd-Fe合金；復雜合金相；原子團；排列
（Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology,
Beijing 100124, China）
Abstract:The scanning electron microscopy and transmission electron microscopy were used to analyze the distributional, compositional and microstructural characteristics of the complex alloy phases (CAPs) formed in the as-cast Al75Pd15Fe10 alloy. For the two CAPs formed during the solidification, the local and long-range features determined by the arrangement of atom clusters were compared, and also the formation conditions were discussed. The results show that there exist two kinds of CAPs formed through different phase transition processes but containing same type of columnar atom clusters with 1.6 nm periodicity as the basic structural building blocks. The two CAPs belong respectively to a decagonal quasicrystal with defects of high density and defective crystalline phase (ε16). Prior to the formation of the ε16 crystalline structure, the quasiperiodic structure forms at higher temperature. Within the compositional range suitable for the formation of an Al-Pd-Fe complex structure, increasing the Pd-content and slowing down the solidification rate will be favorable to form atom clusters with structural integrity, and also favorable to increase the distributional density and establish long-range periodicity for the arrangement of atom clusters.
Key words: Al-Pd-Fe alloy; complex alloy phase; atom cluster; arrangement
