Subregular Model For Formation Enthalpy Of Vb And Vib Group Metal Based Binary Alloys

Formation enthalpy of alloys is a very important parameter for the description of formation and stability of the intermediate phase. It is wildly used in the prediction of amorphous alloys, the calculation of phase diagram etc. Many years has passed for the study and application of VB and VIB group based alloys for their characteristic, such as high melting point, high-strength, high-hardness, high thermal shock resistance, high electrical conductivity and thermal conductivity, high corrosion resistance, and so on. So, theoretical study for the parameters, e.g. the formation enthalpy, elastic constant et al, of VB and VIB group based alloys is very useful.Based on the Miedema theory and the alloy thermodynamic theory, the subregular model is proposed for the formation enthalpy of VB and VIB group based alloys. And then the subregular model is used to calculate the value of formation enthalpy of 468 binary alloys based on the VB and VIB based alloys. It can be found:1. If the value of the formation enthalpy about the 468 binary alloys, which is concerned with the 6 elements of VB and VIB group, is negative, the alloy has the stability intermediate alloys. On the contrary, there exist no stability intermediate alloys.2 The value calculated using Eshelby elastic enthalpy model is smaller than that of Friedel's for the 468 binary alloys concerned with the 6 elements of VB and VIB group.3 The chemical formation enthalpies for TM (TM=VB, VIB group)-M(M=IIIA, IVA, VA, VIB, VIIB, VIIIB group) binary alloys are negative but are positive for TM (TM=VB, VIB group)-M(M=IA, IIA, IB, IIB, IIIB, IVB group) binary alloys.4 The results show that the formation enthalpy calculated by the subregular model is in almost agreement with that of experimental results. The maximum of relative error of calculated formation enthalpy and experimental formation enthalpy is less than 10 percent.