Thermodynamic investigation of phase equilibria in Al–Si–V system
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2018年第9期
论文作者：Qun Luo Kang Li Qian Li
文章页码：1592 - 1601
摘 要：The Al-Si-V system is assessed to understand the phase equilibria of V-containing（3 d transition metal）Al-Si alloys, which are generally of great importance for technical applications. Four annealed alloys were prepared to study the phase equilibria of Al-rich corner（V ≤ 23.3 at.%, Si ≤ 57.6 at.%） in the temperature range of 500-930 ℃. The microstructure and phase constituents of the samples were determined by X-ray diffraction（XRD） and scanning electron microscopy（SEM） equipped with energy dispersive X-ray spectrometer（EDS）, The existence of ternary phase τ(Al0.6 Si1.4 V, TiSi2-type) was confirmed with the composition ranging from 17.98 to 18.59 at.% Al and 48.89-49.20 at.% Si. However, it did not equilibrate with fcc（Al） below 868℃, which was determined by differential scanning calorimetry（DSC）. The Si3 V5 appeared in Al58 5 Si18.3 V23.2 and Al64 7 Si20.2 V15.1 alloys annealed at 500 ℃. It nearly disappeared after3000 h-annealing and its thermodynamic stability was discussed. According to the measured phase relationships, the thermodynamic description of Al-Si-V system was optimized combing with the enthalpies of formation of binary and ternary compounds obtained by density functional theory（DFT）. The Si-V system was modified to obtain the congruent liquidus of Si3 V5 and enthalpy of formation of Si3 V5 and Si2 V with experimental data. By comparing the calculated phase equilibria and phase transitions with experimental data, it showed that a good agreement was reached. The description of Al-Si-V system could be used to guide the development of Al-Si alloys.
Qun Luo1，Kang Li1，Qian Li1,2,3
1. State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering,Shanghai University2. Materials Genome Institute, Shanghai University3. Shanghai Institute of Materials Genome
摘 要：The Al-Si-V system is assessed to understand the phase equilibria of V-containing（3 d transition metal）Al-Si alloys, which are generally of great importance for technical applications. Four annealed alloys were prepared to study the phase equilibria of Al-rich corner（V ≤ 23.3 at.%, Si ≤ 57.6 at.%） in the temperature range of 500-930 ℃. The microstructure and phase constituents of the samples were determined by X-ray diffraction（XRD） and scanning electron microscopy（SEM） equipped with energy dispersive X-ray spectrometer（EDS）, The existence of ternary phase τ(Al0.6 Si1.4 V, TiSi2-type) was confirmed with the composition ranging from 17.98 to 18.59 at.% Al and 48.89-49.20 at.% Si. However, it did not equilibrate with fcc（Al） below 868℃, which was determined by differential scanning calorimetry（DSC）. The Si3 V5 appeared in Al58 5 Si18.3 V23.2 and Al64 7 Si20.2 V15.1 alloys annealed at 500 ℃. It nearly disappeared after3000 h-annealing and its thermodynamic stability was discussed. According to the measured phase relationships, the thermodynamic description of Al-Si-V system was optimized combing with the enthalpies of formation of binary and ternary compounds obtained by density functional theory（DFT）. The Si-V system was modified to obtain the congruent liquidus of Si3 V5 and enthalpy of formation of Si3 V5 and Si2 V with experimental data. By comparing the calculated phase equilibria and phase transitions with experimental data, it showed that a good agreement was reached. The description of Al-Si-V system could be used to guide the development of Al-Si alloys.
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