Y-Al化合物对铝合金性能影响的价电子理论分析

Y是稀土铝合金中常用的添加元素,Y和Al可以形成五种不同的化合物,Y-Al化合物对稀土铝合金的性能有重要的影响.基于固体与分子经验电子理论(EET)和键距差方法(BLD),计算了五种Y-Al化合物的价电子结构和化学键键能,从价电子结构层次探讨了五种Y-Al化合物对稀土铝合金强度、塑性和高温稳定性的影响.计算结果表明,五种Y-Al化合物对铝合金的室温强度都有较好的增强作用;YAl3的塑性最好但稳定性极差;Y3Al2和Y2Al的脆性高,对铝合金的塑、韧性有严重的削弱;YAl2的强度和塑性居中,但稳定性最强,熔点高,对铝合金的室温强度、高温稳定性和高温强度都有显著的贡献.因此,在稀土铝合金的制备中,应促进YAl2相的生成.

Study on effect of Y-Al compounds on aluminum alloy properties with valence electron theory

Y and Al may be formed of five different compounds, which have an important influence on the performance of the rare earth aluminum alloy. The valence electron structures and chemical bond energies of Y-Al compounds were calculated based on the empirical electron theory (EET) and the bond length difference method (BLD). The effect of Y-Al compounds on the strength, ductility and stability of aluminum alloy are studied, and the calculation results show that the five compounds can strengthen the aluminum alloy. YAl₃ has the best ductility but the poor stability; Y₃Al₂ and Y₂Al are brittle and weaken seriously the plastic and toughness of the aluminum alloy; YAl₂ has a significant contribution for the room temperature strength, high temperature stability and high temperature strength of aluminum alloy. Therefore, the formation of YAl₂ should be promoted in the preparation of the RE-Al alloy.