中文摘要：

针对Al-Y合金中的Al Y、Al2Y、Al3Y金属间化合物有关力热性能,采用密度泛函理论、第一性原理以及CASTEP软件进行了理论计算。首先,对五种不同结构金属间化合物的结构进行了优化,并得出了平衡晶格常数。在此基础上,计算得到了它们的生成热、结合能以及弹性系数,并对计算结果进行了理论分析。计算结果表明：在上述五种不同结构的金属间化合物中,其主要的强化相Al2Y合金化形成能力最强,而且结构也较稳定,脆性最强。

英文摘要：

The mechanical and thermal properties of the intermetallic compounds Al Y,Al2 Y and Al3 Y in the Al-Y alloys were theoretically calculated based on density functional theory（ DFT） and first principles,using the software of CASTEP. First,the structures of the five intermetallic compounds were optimized and the equilibrium lattice constants were obtained. On this basis,their formation enthalpy,cohesive energy and elastic constant were calculated and the results were analyzed in theory. It can be conculded that among the five intermetallic compounds of different structures,the ability of alloying of the main strengthening phase Al2 Y is the strongest,and the structure is relatively stable,while its brittleness is the strongest.