Thermodynamic Optimization Of Gallium-Indium-Tin-Zinc System And Its Metastable Phenomenon

Gallium-based liquid metal has gradually become a hot research direction in recent years.Its excellent properties such as high fluidity,high thermal conductivity and low melting point are widely used in various fields.It is composed of four elements: gallium,indium,tin and zinc.The Ga-In-Sn-Zn system contains a variety of gallium-based liquid metals.However,since the thermodynamic database of the system has not been established,there is a lack of theoretical guidance when improving the performance of materials in this system and developing new materials.Constant trial-and-error process is often required to achieve the goal,which greatly increases the research and development cycle and capital investment.In order to solve the above problems,this paper aims to optimize the thermodynamic parameters of each phase in the Ga-In-Sn-Zn system and establish a thermodynamic database of the system.Due to the existence of metastable phenomena in this system,the application of intercepting metastable relative to gallium-based liquid metals is very beneficial,so the metastable phenomenon in this system is studied at the same time.The main research contents include:Use the Einstein heat capacity model and its low-order and high-order anharmonic correction models to fit the experimental data of pure component metastable phase β-Ga heat capacity to obtain multiple sets of lattice stability expressions,and then use each The thermodynamic data results calculated by the lattice stability expression are compared with the experimental values,and the most reliable lattice stability expression of β-Ga is obtained,and the thermodynamic optimization of β-Ga is completed.Afterwards,the factors affecting the stability of the metastable β-Ga phase were studied.Four sub-ternary systems(Ga-In-Sn,Ga-In-Zn,Ga-Sn-Zn,and In-Sn-Zn)in the Ga-In-Sn-Zn system were investigated using the CALPHAD method in combination with experimental data and existing thermodynamic information for thermodynamic optimization.The thermodynamic parameters of Ga-In-Sn and Ga-Sn-Zn liquid phases were optimized by using the subnormal solution model,and the thermodynamic information of Ga-In-Zn and In-Sn-Zn was obtained by extrapolation calculation.By comparing the elemental phase diagram with the experimental values,the accurate thermodynamic parameters of the ternary system can be obtained,so that the thermodynamic database of the Ga-In-Sn-Zn system can be established.Finally,the phase equilibrium information of Ga-In-Sn-Zn was calculated using the thermodynamic database.The influence of the metastable phenomenon in the Ga-In-Sn-Zn system was studied from three aspects of sample quality,subcooling degree and micro-additives by using low temperature DSC experimental equipment,and the metastable phase could be in a stable state.The obtained experimental data were compared and analyzed to explore the factors affecting the metastable phenomenon in this system.