(上海交通大学 材料科学与工程学院，上海 200240)
摘 要: 采用基于密度函数理论的赝势平面波方法和广义梯度近似对TiB2和TiB化合物的弹性性质和电子结构进行了理论计算，并用Voigt-Reuss-Hill方法计算得到多晶体的弹性模量和切变模量。结果表明：TiB2和TiB的弹性模量分别为599 GPa和443 GPa，切变模量分别为268.5 GPa和193.5 GPa，Pugh 定律和泊松比等经验判据表明TiB2比TiB脆性更大；并从这两种化合物的电子结构对其弹性性质的差异进行了讨论。
关键字: 弹性性质；电子结构；第一性原理
（School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China）
Abstract:First-principles calculations were carried out to investigate the elastic properties and electronic structure of TiB2 and TiB, using the method of ultrasoft pseudopotential within the generalized gradient approximation based on density functional theory. The moduli of the polycrystals for TiB2 and TiB were calculated from the theoretical elastic constants by Voigt-Reuss-Hill averaging scheme. The calculated results of elastic properties agree well with the experimental values and those calculated in the literature. Based on several empirical criterions of Pugh rule and Poisson’s ratio ν, TiB2 and TiB are brittle in nature, and the brittleness of TiB2 is higher than that of TiB. The difference in elastic properties between TiB2 and TiB is discussed with their electronic structures.
Key words: elastic properties; electronic structure; first-principles
