Microdomain atomic structure of Zr50Pd40Al10 metallic glasses and its formation mechanism
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2019年第3期
论文作者：Kai Li Fangliang Gao Yu-Jen Chou Kaixiang Shen Guoqiang Li
文章页码：248 - 253
摘 要：Zr-based Zr50Pd40Al10 metallic glasses has not only crystalline phases of about 5 nm in diameter but also amorphous phases. In this work, the radial distribution functions（RDFs） of amorphous structure of Zr50Pd40Al10 metallic glasses were firstly measured by electron diffraction, and then Reverse Monte Carlo（RMC） optimization accompanied by density functional theory（DFT） calculations. The amorphous structure has not only short-range order but also good medium-range order. In the RDFs of its amorphous structure, the first and the second peaks are located at 2.96 ? and 4.79 ?, respectively. Partial radical distribution functions（PRDFs） show that the contributions of the first and the second nearest-neighbor distances of various atom pairs to the G（r） peak values, and the first nearest-neighbor distances of Pd–Zr and Zr–Zr atom pairs are the sources of main G（r） peak values between 2? and 6?. The competition mechanism for generating the Pd25Zr55 Al20 amorphous phase and the intermetallic crystalline phase Pd11Zr9 is associated with the differences of atomic radius, the proportion, and the melting point of different atoms, as well as the heat of mixing between atoms, leading to an equilibrium state of the two phases. Accordingly, a composite system with intertwined nanocrystals and amorphous phases is in turn formed, and improves the stability of the material.
Kai Li1,2,3，Fangliang Gao1,2,3，Yu-Jen Chou3，Kaixiang Shen4，Guoqiang Li1,2,3
1. State Key Laboratory of Luminescent Materials and Devices, South China University of Technology2. Engineering Research Center on Solid-State Lighting and Its Informationisation of Guangdong Province, South China University of Technology3. Department of Electronic Materials, School of Materials Science and Engineering, South China University of Technology4. School of Physics and Telecommunications Engineering, South China Normal University
摘 要：Zr-based Zr50Pd40Al10 metallic glasses has not only crystalline phases of about 5 nm in diameter but also amorphous phases. In this work, the radial distribution functions（RDFs） of amorphous structure of Zr50Pd40Al10 metallic glasses were firstly measured by electron diffraction, and then Reverse Monte Carlo（RMC） optimization accompanied by density functional theory（DFT） calculations. The amorphous structure has not only short-range order but also good medium-range order. In the RDFs of its amorphous structure, the first and the second peaks are located at 2.96 ? and 4.79 ?, respectively. Partial radical distribution functions（PRDFs） show that the contributions of the first and the second nearest-neighbor distances of various atom pairs to the G（r） peak values, and the first nearest-neighbor distances of Pd–Zr and Zr–Zr atom pairs are the sources of main G（r） peak values between 2? and 6?. The competition mechanism for generating the Pd25Zr55 Al20 amorphous phase and the intermetallic crystalline phase Pd11Zr9 is associated with the differences of atomic radius, the proportion, and the melting point of different atoms, as well as the heat of mixing between atoms, leading to an equilibrium state of the two phases. Accordingly, a composite system with intertwined nanocrystals and amorphous phases is in turn formed, and improves the stability of the material.
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