分子轨道理论在分析合金相稳定性方面的应用

APPLICATION OF MOLECULAR ORBITAL THEORY TO ANALYSIS OF PHASE STABILITY FOR ALLOYS

应用分子轨道理论分析了面心立方过渡族金属三元合金的固溶度,采用特征点成分平均法计算了三元合金相图的不同等温截面的43个γ/(γ+σ),γ/(γ+μ),和γ/(γ+γ′)相界线的临界■_d值■_(dc)。得到了γ/(γ+μ)相变的■_(dc)值与温度的关系式,并对分析的准确度进行了讨论发现存在着临界平均键合级次■_(oc),它可以和■_(dc)一道用来分析合金相的稳定性。

In this paper, the application of molecular orbital theory to the analysis of phase stability of alloys is outlined. The critical M_d values (M-_(dc)) of the γ/(γ+σ),γ/(γ+μ) and γ/(γ+γ') phase boundaries in some ternary alloy phase diagrams at various temperatures are calculated by averaging the M_d values of several selected characteristic points at the phase boundaries. Approximate equations for the temperature dependence of the critical M_d of γ/ (γ+σ), γ/ (γ+μ) and γ/(γ+γ') phase boundaries are established. The accuracy of the analysis is discussed in detail. It is found for the first time that the average value of the bond order, B_o ,at the phase boundaries is also approximately a constant and therefore a critical average bond orderB_(oc). like M_(dc), can be introduced for the analysis of phase stability.