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采用第一原理平面波法,计算AuCd合金中B2、γ2’和ζ2’相的能带结构、晶格参数和总能量,计算结果和实验数据符合得很好。计算结果表明:对于B2、γ2’和ζ2’3种不同的结构,能带结构在费米面以下非常相似;费米面以上的能带曲线陡峭,而以下的却很平滑。γ2’相具有最低的系统总能量,稳定顺序依次为γ2’>ζ2’>B2。AuCd合金γ2’相的晶格参数在释放内部应力过程中,总是遵循一个简单规律,即晶格参数a变小,b和c变大。实验测得的这3个晶格参数的变化趋势和本研究计算得到的理论结果完全一致。
The band structure, lattice parameters and total energies of B2, γ2 ’and ζ2’ phases in AuCd alloys were calculated by the first principle plane wave method. The calculated results are in good agreement with the experimental data. The calculated results show that the energy band structure is very similar to the three structures B2, γ2 ’and ζ2’under the Fermi surface. The energy band curves above the Fermi surface are steep, while the ones below are very smooth. γ2 ’phase has the lowest total system energy, and the order of stability is γ2’> ζ2 ’> B2. The lattice parameters of the γ2 ’phase of AuCd alloy always follow a simple law during the process of releasing internal stress, ie, the lattice parameter a becomes smaller and b and c become larger. The trend of these three lattice parameters experimentally measured is in good agreement with the theoretical result calculated in this study.