材料理论硬度与键合性质的关系研究

以往的研究表明材料硬度与键合性质之间有密切的联系,但材料硬度和晶体体弹模量（B）、剪切模量（G）之间的联系不存在一一对应关系.基于密度泛函理论,在广义梯度近似的计算条件下得到了多种典型晶体材料的结构参数和弹性模量参数,将参数代入Simunek A.理论小组的理论硬度计算模型可获得晶体的理论硬度值.通过分析晶体的硬度值与体弹模量（B）、剪切模量（G）之间的关系,认为“难压缩”并不等同于“高硬度”;通过对晶体键密度和键布居等成键电子结构信息的分析,改进了Simunek理论小组硬度计算模型中一个参数的获取方法,使计算结果更具合理性;通过定性分析认为拥有强的共价键和三维立体空间结构是晶体具有高硬度的典型特征,为今后新型超硬材料的理论研究和实验合成提供重要参考.

Research on the Relationship Between Theoretical Material Hardness and Bonding Properties

Previous research shows that the material hardness and the bond properties have close contacts, but the relationship between hardness of crystal and the bulk modulus of crystal （ B ） as well as the relationship between hardness of crystal and shear modulus （ G ） are not one by one responded. Under the circumstance of the generalized gradient approximation, structure parameters and elastic modulus of various typical crystal materials are obtained based on the density functional theory. Based on the Simunek A, theory model, the theoretical hardness is calculat- ed. Then, the relationship between hardness of crystal and the bulk modulus of crystal （ B ） as well as the relation- ship between hardness of crystal and shear modulus （ G ） are analyzed. The result shows that ＂difficult to compress＂ is not equal to ＂super hardness＂ . An improvement on acquiring a parameter in the Simunek theory group model has been made by analyzing the crystal bond density and bond population, which can make calculation reasonable. Quali- tative analysis shows that the typical feature of high crystal hardness is high hardness crystalline compound and three dimensional structures, it provides an important guide for future theoretical study and experimental synthesis of new super-hard material.