(北京工業(yè)大學(xué) 固體微結(jié)構(gòu)與性能研究所，北京 100124)
摘 要: 應(yīng)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(fù)雜合金相的分布、成分以及微觀結(jié)構(gòu)特征。針對(duì)凝固過(guò)程中形成的兩種復(fù)雜合金相，對(duì)比分析其中原子團(tuán)排布的局部及長(zhǎng)程特征，并對(duì)其形成條件進(jìn)行討論。結(jié)果表明：凝固組織中同時(shí)存在兩種經(jīng)歷不同相變過(guò)程而形成的、但含有以同類(lèi)柱狀(1.6 nm周期)原子團(tuán)為基本結(jié)構(gòu)單元的復(fù)雜合金相，它們分別屬于具有高密度缺陷的十面體準(zhǔn)晶和相關(guān)近似晶體相(ε16)。與ε16結(jié)構(gòu)相比，準(zhǔn)周期結(jié)構(gòu)的形成溫度區(qū)間相對(duì)較高；在Al-Pd-Fe復(fù)雜合金相結(jié)構(gòu)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(tuán)的充分形成，也有利于原子團(tuán)分布密度的增大以及長(zhǎng)程排列周期性的建立。
關(guān)鍵字: Al-Pd-Fe合金；復(fù)雜合金相；原子團(tuán)；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
