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Research On The Comparison Of Wilson Equation And Regular Solution Model In The Al-based Liquid Alloy Systems

Posted on:2004-01-23Degree:MasterType:Thesis
Country:ChinaCandidate:H T GuanFull Text:PDF
GTID:2121360095951407Subject:Non-ferrous metallurgy
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Aluminum has been widely used in the production of non-ferrous metal alloys and fabrication of modern compound materials for its light weight and superior mechanical strength and corrosion-resistant properties. The development history of aluminum metallurgy is introduced, and the present situation of the industry of aluminum and aluminum alloys in China is also talked about in this thesis. The significance and necessity of research on the thermodynamic properties of Al-based liquid alloys are also emphasized.In this thesis, the thermodynamic properties of 24 binary Al-based liquid alloys are then fitted with Wilson equation and the regular solution model. The results show that Wilson equation and the regular solution model are suitable for the strongpositive deviation systems, but not for the strong negative and coexisted deviation ones. As to the weak deviation systems, they are fitted well with Wilson equation and regular solution model. Relatively, Wilson equation fits better than regular solution model, but the symmetrical systems are fitted better with regular solution model. The results also show that Wilson equation and regular solution model are not suitable for the systems that had immiscible gaps in the liquid phases.Then based on the results in binary liquid alloys, thermodynamic properties of 6 ternary and 1 quaternary liquid alloys are predicted and compared. For most multi-component systems that are investigated, the predicted activities of Al with Wilson equation are in better agreement with the experimental results. The results also indicate that the suitability of Wilson equation and regular solution model to multi-component systems is restricted by the binary systems and temperature. Generally speaking, if the fitted results are not satisfactory for binary systems, the prediction is also bad for multi-component systems that include the binary ones, and the more the temperatures at which the multi-component system is predicted are close to that of the binary systems, the better the predicted results with Wilson equation. But it is not for the regular solution model, because the influence of temperature has been taken into account when the parameters are calculated.The comparison of application of Wilson equation and regular solution model in the Al-based liquid alloys shows that the suitability of regular solution model is restricted because it is only fit for the systems in which the components has the approximate size and structure. Wilson equation has more extensive and stronger adaptation ability, but its prediction is influenced by binary systems and temperature. For calculations that need more accuracy, the relationship between the energy parameters and temperature should be considered.In conclusion, the application of Wilson equation to the calculation of thermodynamic properties of Al-based liquid alloys succeeds and a foundation for the theoretical analysis of both the electrolysis and electrorefming of aluminum metallurgy and the development and calculation of process design of Al-based alloys is provided.
Keywords/Search Tags:Wilson equation, regular solution model, Al-based liquid alloys, activity, fitting, prediction
PDF Full Text Request
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