Ta合金化对γ′-Ni3Al相弹性性质与电子结构的影响

Effect of Alloying Element Ta on Elastic Properties and Electronic Structure of γ′-Ni3Al Phase

摘要:

基于密度泛函理论，采用第一性原理赝势平面波方法计算了合金元素Ta掺杂对γ′-Ni3Al相弹性常数与电子结构的影响。计算结果表明：Ta的加入能有效提高Ni3Al相的弹性性质，使其弹性模量提高12.86%，形成的Ni3(Al,Ta)金属间化合物是一种塑性相，但其本征脆性要比Ni3Al大；使用总化学键的重叠布居，定量地计算了金属间化合物的共价键性能，结果显示Ta的添加能增加Ni3Al相共价键的强度；价电荷密度及态密度的进一步分析指出：Ni3(Al,Ta)相中化学键有方向共价键和金属键共存的特征

Abstract:

The elastic properties and electronic structure of Ta-doped γ′-Ni3Al Phase have been investigated by the pseudo-potential plane wave (PP-PW) method within density functional theory. The calculated results show that Ta can effectively strengthen the elastic properties of Ni3Al alloys, which makes the Young’s modulus increase by 12.86%. The Ni3(Al,Ta) intermetallic compound behaves in ductile, but is more brittle than Ni3Al in nature. Using a sum of overlap populations of all bonds in the supercell, the covalent bonding of intermetallic compounds was evaluated quantitatively. It is found that Ta can increase the covalent bonding of γ′-Ni3Al. The bond characters were also analyzed using valence charge densities and total density of states, and the results indicate the chemical bonds in γ′-Ni3(Al,Ta) can be classified as a mixture of directional covalent and metallic characteristic