| Computer applications in material science refers to the new technology that the computer as a means of calculating the theoretical and the inherent nature of the material, the structure and composition, synthesis and processing.which aims to make people can take the initiative to optimize and control the structure, function and process technology, develop and preparae new materials. The process of material design is promoted by rapidly development of computational materials science, as one of the thermodynamic calculation of phase diagram calculation CALPHAD (CALculation of PHAse Diagram) technology, based on thermodynamic model, widely used in multi-component material systems phase diagram calculation, predicting formation phase, phase transition temperature, etc, which providing the crucial theoretical guidance of material design.Precious metal alloys are used in aviation, aerospace, military and other key materials industries, arounding the phase diagram of materials, completing the precious metal alloy basis and research system, which provide a favorable support of precious metal alloys application. In this paper, selected the representative Au-Pd alloy in the application of this subject filed, with the Zr element forming a multi-component alloy phase diagram, which laid the high-performance design of a new precious metal alloys and development of theoretical and applied foundationIn this paper, calculated the Ir-Pt-Zr and Au-Pt-Zr ternary alloy phase diagrams by CALPHAD technique, forecasted the alloy design process by thermodynamics software pandat, the main work is as follows:(1) Evaluated the Ir-Pt binary system by CALPHAD technique, a set of self-consistent thermodynamic parameters were obtained by the optimization of Ir-Pt binary system according to the erimental data and thermodynamic data.The Ir-Pt binary phase diagram was calculated according to the thermodynamic parameters.The calculated phase diagrams and thermodynamic information get a good agreement with the experimental results(2) Analyzing the thermodynamic models and the Gibbs free energy expression of Pt-Zr and Ir-Zr binary alloy phase diagrams and the two binary alloy phase diagrams were calculated by pandat Software.The calculated phase diagram and phase diagram of the standard experiments were compared, the results of comparative analysis showed: calculated phase diagrams and experimental phase diagrams in terms of phase composition and the phase transition temperature and thermodynamic information were matched well, which indicating the thermodynamic data and models of Pt-Zr and Ir-Zr two binary alloy systems are accurate and reliable. If the thermodynamic database was completed, thermodynamic calculations can provide reasonable forecast for alloy components and provide reliable support for the thermodynamic calculation of ternary alloy phase diagram.(3) Extrapolated the liquidus projection, isothermal sections at different temperatures and vertical section of Ir-Pt-Zr ternary alloy by Pandat software. Selecting five key experimental points:1#alloy (42Ir-29Pt-29Zr),2#alloy (30Ir-35Pt-35Zr)、3#alloy (20Ir-40Pt-40Zr).4#alloy (14Ir-43Pt-43Zr)、5#alloy (8Ir-46Pt-46Zr), analyzing detailedly the solidification process of precipitation in order to determine the organizations consistent at the room temperature and detect the possible phase in the precipitation process. The results showed that:the detected room temperature tissue organization consistent with the prediction, indicating that the thermodynamic equilibrium calculation software Pandat is accurate and reliable.(4) Analyzing the thermodynamic models and the Gibbs free energy expression of Au-Zr and Au-Pt binary alloy phase diagrams and the two binary alloy phase diagrams were calculated by pandat Software.The calculated phase diagram and phase diagram of the standard experiments were compared, the results of comparative analysis showed: calculated phase diagrams and experimental phase diagrams in terms of phase composition and the phase transition temperature and thermodynamic information were matched well, which indicating the thermodynamic data and models of Au-Zr and Au-Pt two binary alloy systems are accurate and reliable.(5) Extrapolated the liquidus projection, isothermal sections at different temperatures and vertical section of Au-Pt-Zr ternary alloy by Pandat software. Selecting two key experimental points:1#alloy (44Au-28Pt-28Zr)、2#alloy (28Au-36Pt-36Zr), analyzing detailedly the solidification process of precipitation in order to determine the organizations consistent at the room temperature and detect the possible phase in the precipitation process. The results showed that:the detected room temperature tissue organization consistent with the prediction, indicating that the thermodynamic equilibrium calculation software Pandat is accurate and reliable.(6) The Ir-Pt-Zr ternary alloy phase diagram calculations were verified with experimental results, but because there are some errors during the experiment, this research is still need further experimental work. |
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