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.
The systematic science of alloys(SSA)is a framework of the total energy and total volume able to be separated.The volume sequences of characteristic atoms at the central sites of the basic clusters in the fcc-based Au-Cu system are separated out from the experimental volumes of L10-AuCu and L12-AuCu3 compounds at room temperature only,by nine volume V-functions. From these volume sequences,the volumes,volumes of formation,ordering(excess)volumes and volume mismatch degrees of the L10-AuCu,L12-AuCu3 and L12-Au3Cu compounds,Au3Cu-,AuCu-and AuCu3-type ordered alloys with maximal ordering degree, and disordered Au1-xCux alloys are calculated.Among these functions,only ordering volumes of the compounds and ordered alloys obtained by the 6th V-function are negative,i.e.,the destruction of the superlattice is accompanied by an increase in volume,which is identical with the experimental results.Accompanying conclusions,the different descriptions of volumetric properties between traditional alloy theories and SSA framework are discussed.
Isometric heat capacity cv and isobaric heat capacity cp of Pt with stable and metastable phases were calculated by using pure element systematic theory. These results are in excellent agreement with of SGTE(Scientific Group Thermodata Europe) database and JANAF(Joint Army-Navy-Air Force) experimental values. The calculation results of cv and cp of Pt metal in natural state are in good agreement with those calculated by FP(first-principles) method. It is found that the electron devotion to heat capacity is important to adjust in OA(one-atom) method while calculating heat capacity. The full information about thermodynamic properties of Pt metal with stable and metastable phases,such as entropy(S),enthalpy(H) and Gibbs energy(G) were calculated from 0K to random temperature. The results are in good agreement with JANAF experimental value. In contrast to SGTE database,the thermodynamic properties from 0K to 298.15 K are implemented.
