铝基金属间化合物论文：铝基金属间化合物电子结构力学性能功函数第一性原理计算

铝基金属间化合物论文：铝基金属间化合物电子结构力学性能功函数第一性原理计算

【中文摘要】铝基金属间化合物以诸多优异的化学、物理、电学、磁学和力学性能使其有望在航空航天、微电子、交通运输以及国防军工等高新技术领域得到广泛的应用。但是它们的室温脆性严重的限制了它们的应用。近来的一些理论研究显示材料的力学特性,尤其是金属间化合物固有的脆性,应归因于它们本身的化学键的性质或它们的电子结构。然而由于实验条件的限制,通过电子结构信息来深入理解铝基金属间化合物力学性质的相关研究很少。因此,从电子结构的角度去研究和分析金属间化合物的力学性能尤其是脆化本质具有很重

要的意义。随着近年来计算机技术和计算材料科学的发展,基于密度泛函理论的第一性原理计算方法已成为计算固体及表面性质的有效

工具。论文主要分两大部分:第一部分详细计算了几种典型的立方结构的二元、三元铝基金属间化合物的晶体及电子结构和力学性能;第二部分计算了三元铝基金属间化合物AlCu2Ti、AlCu2Zr、AlCu2Hf和AlCu2Mn的一些相关的块体及表面性质。论文主要包括以下内容:（1）采用第一性原理方法计算了几种立方结构铝基金属间化合物AlCu3、AlCu2Zr和AlZr3的稳定性、弹性、电子结构和力学性能。通过计算所得到的弹性常数与实验值吻合很好。形成能与结合能的计算结果表明:AlCu3、AlCu2Zr和AlZr3都有较好的稳定性和合金化能力,且AlZr3的稳定性最高,其次是AlCu2Zr,最后是AlCu3。通过计算得到

了AlCu3、AlCu2Zr及AlZr3的弹性常数( C11、C1 2及C 44),进而得到合金的弹性模量,最后进一步分析讨论了材料的力学性质。（2）利用第一性原理方法计算了金属间化合物AlCu2Ti、AlCu2Mn、AlCu2Zr 和AlCu2Hf的稳定性、电子结构、力学性能以及表面性能。通过形成能与结合能的计算得出:在这四种金属间化合物中,合金化能力和稳

定性最强的是AlCu2Zr相,这主要原因在于其费米能级处较少的态密度值,通过进一步计算得到AlCu2Ti、AlCu2Mn、AlCu2Zr和AlCu2Hf 的弹性常数( C11、C1 2及C 44)及弹性模量,还计算了其（100）和（110）面的表面能及表面电子功函数,在此基础上进一步分析讨论材料的块体及表面性质,并找出其内在的联系,分析其内在的变化机制。

【英文摘要】Al-based intermetallic compounds have long been known to possess attractive chemical, physical, electrical, magnetic and mechanical properties that are often superior to those of ordinary metals. Therefore, they have wide application, especially, in the aerospace field, microelectronic, motorized vehicles and domestic industry. But their brittleness at room temperature has severely hampered their applications. Recent theoretical investigations have revealed that the mechanical behavior, in particular the intrinsic brittleness of intermetallics should be attributed originally to the nature of their chemical bonds or their electronic structure, although various factors may cause

different embrittlement cases. However, only few researches for deeply understanding the electronic structures and mechanical properties of Al-based intermetallic compounds through the electronic structure information were introduced because of the restrict of the experimental condition. Therefore, it is crucial to investigate the electronic structures in detail in order to understand the brittleness of the alloys completely.It is well known that first principles calculations based on density functional theory is a capable way to caculate the properties of solid and surface, and predict many material qualities and their tendency of variations from microscopic view. Firstly, we carry out a systematic investigation of electronic structure and mechanical properties of typical cubic structure of Al-based intermetallic compounds （AlCu3, AlCu2Zr and AlZr3） by first principles calculations. Secondly, we report the relationship between the bulk and surface properties of ternary Al-based intermetallic compounds （AlCu2Ti, AlCu2Mn, AlCu2Zr and AlCu2Hf）. The main contents of our work are:（1）

First-principles calculations were performed to study on alloying stability, electronic structure and mechanical properties of Al-based intermetallic compounds （AlCu3,