As an example of the La-Mg-Y system, the method how to set up the themaodynamic model of individual phases was introduced in the process of thermodynamic optimization. The solution phases （liquid, body-centered cubic...As an example of the La-Mg-Y system, the method how to set up the themaodynamic model of individual phases was introduced in the process of thermodynamic optimization. The solution phases （liquid, body-centered cubic, face-centered cubic, hexagonal close-packed and double hexagonal close-packed） were modeled with the Redlich-Kister equation. The compound energy model has been used to describe the thermodynamic functions of the intermetallic compounds in the La-Mg-Y systems. The compounds Mg2Y, Mg24Y5, Mg12La, Mg17La2, Mg41Las, Mg3La and Mg2La in the La-Mg-Y system were treated as the formulae （Mg,Y）2（La,Mg,Y）, Mg24（La,Mg,Y）4Y, Mg12（La, Y）, Mg17（La,Y）2, Mg41（La,Y）5, Mg3（La,Mg,Y） and Mg2（La, Y）, respectively. A model （La, Mg,Y）0.5（La,Mg,Y）0.5 was applied to describe the compound MgM formed by MgLa and MgY in order to cope with the order-disorder transition between body-centered cubic solution （A2） and MgM with CsCl-type structure （B2） in the La-Mg-Y system. The Gibbs energies of individual phases were optimized in the La-Mg, La-Y and La-Mg-Y systems by CALPHAD technique. The projection of the liquidus surfaces for the La-Mg-Y system was predicted. The Mg-based alloys database including 36 binary and 15 ternary systems formed by Mg, Al, Cu, Ni, Mn, Zn and rare earth elements was set up in SGTE standard.展开更多
The systematic science of alloys(SSA)is a framework of the total energy and total volume able to be separated.The potential energy sequences of characteristic atoms at the central sites of the basic clusters in the fc...The systematic science of alloys(SSA)is a framework of the total energy and total volume able to be separated.The potential energy sequences of characteristic atoms at the central sites of the basic clusters in the fcc-based lattice Au-Cu system are separated out from smaller experimental heats of formation of L10-AuCu and L12-AuCu3 compounds only,by nine potential energy E-functions and through the use of structural unit inversion method.From these potential energy sequences,the potential energies and heats of formation of the disordered Au1-xCux alloys at 0 K are calculated.The potential energies,heats of formation and Tc-temperatures of order-disorder transitions of the L10-AuCu,L12-Au3Cu and L12-AuCu3 compounds,as well as the Au3Cu-,AuCu-and AuCu3-type ordered alloys with maximal ordering degrees are calculated too.The results show that the 5th E-function may be chosen for developing it into the free energy-,enthalpy-,vibrational energy-and vibrational entropy-functions for describing thermodynamic properties of the compounds,ordered and disordered phases and for establishing the phase diagram of the Au-Cu system in the future.展开更多
基金Acknowledgements： The project was supported by the National Natural Science Foundation of China （No. 50471058）, the Provincial Natural Science Foundation of Hunan （No. 08JJ3099）.
基金Acknowledgements： The project was supported by the National Natural Science Foundation of China （No. 50471058）, the Provincial Natural Science Foundation of Hunan （No. 08JJ3099）.
基金This work was financially supported by the National Natural Science Foundation of China (Nos. 50471095 and 50271008).
文摘As an example of the La-Mg-Y system, the method how to set up the themaodynamic model of individual phases was introduced in the process of thermodynamic optimization. The solution phases （liquid, body-centered cubic, face-centered cubic, hexagonal close-packed and double hexagonal close-packed） were modeled with the Redlich-Kister equation. The compound energy model has been used to describe the thermodynamic functions of the intermetallic compounds in the La-Mg-Y systems. The compounds Mg2Y, Mg24Y5, Mg12La, Mg17La2, Mg41Las, Mg3La and Mg2La in the La-Mg-Y system were treated as the formulae （Mg,Y）2（La,Mg,Y）, Mg24（La,Mg,Y）4Y, Mg12（La, Y）, Mg17（La,Y）2, Mg41（La,Y）5, Mg3（La,Mg,Y） and Mg2（La, Y）, respectively. A model （La, Mg,Y）0.5（La,Mg,Y）0.5 was applied to describe the compound MgM formed by MgLa and MgY in order to cope with the order-disorder transition between body-centered cubic solution （A2） and MgM with CsCl-type structure （B2） in the La-Mg-Y system. The Gibbs energies of individual phases were optimized in the La-Mg, La-Y and La-Mg-Y systems by CALPHAD technique. The projection of the liquidus surfaces for the La-Mg-Y system was predicted. The Mg-based alloys database including 36 binary and 15 ternary systems formed by Mg, Al, Cu, Ni, Mn, Zn and rare earth elements was set up in SGTE standard.
基金Project(50471058)supported by the National Natural Science Foundation of ChinaProject(08JJ3099)supported by the Natural Science Foundation of Hunan Province,China
文摘The systematic science of alloys(SSA)is a framework of the total energy and total volume able to be separated.The potential energy sequences of characteristic atoms at the central sites of the basic clusters in the fcc-based lattice Au-Cu system are separated out from smaller experimental heats of formation of L10-AuCu and L12-AuCu3 compounds only,by nine potential energy E-functions and through the use of structural unit inversion method.From these potential energy sequences,the potential energies and heats of formation of the disordered Au1-xCux alloys at 0 K are calculated.The potential energies,heats of formation and Tc-temperatures of order-disorder transitions of the L10-AuCu,L12-Au3Cu and L12-AuCu3 compounds,as well as the Au3Cu-,AuCu-and AuCu3-type ordered alloys with maximal ordering degrees are calculated too.The results show that the 5th E-function may be chosen for developing it into the free energy-,enthalpy-,vibrational energy-and vibrational entropy-functions for describing thermodynamic properties of the compounds,ordered and disordered phases and for establishing the phase diagram of the Au-Cu system in the future.
