Formation of ordered precipitates in Al-Sc-Er-（Si/Zr） alloy from first-principles study
来源期刊：JOURNAL OF RARE EARTHS2021年第5期
论文作者：Xiaomin Liu Qian Wang Chuan Zhao Hongping Li Mingliang Wang Dong Chen Haowei Wang
文章页码：609 - 620
摘 要：The nucleation properties and stability of the ordered precipitates in Al-Sc-Er alloy were extensively studied by first-principles calculation.The calculated substitutional formation energy reveals that the dissolved Sc or Er in the Al matrix is very favorable to substitute the X sublattice site in L12-Al3 X（X=Sc/Er）.The calculated solubility curve demonstrates the significant contribution of vibrational entropy to nucleation.The interface energies for Al/Al3 Sc,Al/Al3 Er and Al3 Sc/Al3 Er were calculated in the three directions of [100],[110] and [111],and we find that the interface structure in（100） plane is the most desirable,and the interface energy of Al/Al3 Er is the largest.Regardless of temperature and Sc/Er ratio,the L12-Al3 ScxEr1-x precipitation phase mainly forms as the core-shell structure with Al3 Er as the core and Al3 Sc as the shell due to lower nucleation energy.The core-shell structure behaves higher stability once the particle radius is greater than 1 nm.Furthermore,the thermodynamic driving force for the segregating of Si or Zr in Al-Sc-Er alloy should accelerate the precipitation kinetics,where Si partitions occur preferentially to the Al3 Er and Zr partitions preferentially to the Al matrix.Overall,these theoretical results can offer solid explanations to the available experimental results.
Xiaomin Liu1,2，Qian Wang2，Chuan Zhao3，Hongping Li4，Mingliang Wang1，Dong Chen1,2,5，Haowei Wang2
1. State Key Laboratory of Metal Matrix Composites,Shanghai Jiao Tong University2. School of Materials Science & Engineering,Shanghai Jiao Tong University3. Shanghai Institute of Satellite Engineering4. Shanghai Aircraft Design and Research Institute
摘 要：The nucleation properties and stability of the ordered precipitates in Al-Sc-Er alloy were extensively studied by first-principles calculation.The calculated substitutional formation energy reveals that the dissolved Sc or Er in the Al matrix is very favorable to substitute the X sublattice site in L12-Al3 X（X=Sc/Er）.The calculated solubility curve demonstrates the significant contribution of vibrational entropy to nucleation.The interface energies for Al/Al3 Sc,Al/Al3 Er and Al3 Sc/Al3 Er were calculated in the three directions of [100],[110] and [111],and we find that the interface structure in（100） plane is the most desirable,and the interface energy of Al/Al3 Er is the largest.Regardless of temperature and Sc/Er ratio,the L12-Al3 ScxEr1-x precipitation phase mainly forms as the core-shell structure with Al3 Er as the core and Al3 Sc as the shell due to lower nucleation energy.The core-shell structure behaves higher stability once the particle radius is greater than 1 nm.Furthermore,the thermodynamic driving force for the segregating of Si or Zr in Al-Sc-Er alloy should accelerate the precipitation kinetics,where Si partitions occur preferentially to the Al3 Er and Zr partitions preferentially to the Al matrix.Overall,these theoretical results can offer solid explanations to the available experimental results.
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