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采用基于密度泛函理论第一性原理的CASTEP软件包计算α-Al_2O_3的晶体结构和电子结构。进而研究力学性能和电子结构的关系。优化后的菱面体晶胞参数为a=5.07(?),α=55.18°,与文献值相比,相对误差分别是-0.98%,-0.18%。分析α-Al_2O_3晶体总态密度、分波态密度及Mulliken电荷布居,发现Al-O间主要作用除离子键之外,还有s-p杂化,电子有一定的离域性,表明Al-O间存在共价成分。这两者的共同作用,使刚玉有高弹性模量和硬度。同时使滑移系统偏少,出现脆性,而电子的离域性对提高韧性有一定作用。
The crystal structure and electronic structure of α-Al 2 O 3 were calculated by CASTEP software package based on the first principle of density functional theory. Then study the relationship between mechanical properties and electronic structure. The optimized rhombohedral unit cell parameters are a = 5.07 (?) And a = 55.18 °, respectively. The relative errors are -0.98% and -0.18%, respectively. Analysis of total state density, partial state density and Mulliken charge of α-Al 2 O 3 crystals revealed that the main role of Al-O was sp hybridization in addition to the ionic bond and the electrons had a certain delocalization, indicating that Al-O There are covalent components. The combined effect of both makes corundum a high modulus of elasticity and hardness. At the same time, the slippage system is too small and brittle, while the delocalization of electrons has a certain effect on improving the toughness.