物理化学学报Issue(2)：253-260,8.DOI:10.3866/PKU.WHXB201412242
Al代位合金化对D88-Ti5Si3力学性能与电子结构影响的第一性原理研究
First-Principles Study into the Effect of Substitutional Al Alloying on the Mechanical Properties and Electronic Structure of D88-Ti5Si3
摘要
Abstract
The influence of the substitution of Al for Si on the structural stability and mechanical properties of D88-Ti5Si3 was determined using first-principles pseudopotential plane-wave methods based on density functional theory. Several parameters including formation enthalpies ((ΔHf), cohesive energies (ΔEcoh), bulk modulus (B), shear modulus (G), Poisson′s ratio (ν), Cauchy′s pressure (C12-C66,C13-C44), metal icity (fm), and Peierls stress (τP-N) were calculated. To develop a better understanding of the effects of substitutional Al al oying on the toughness/brittleness of D88-Ti5Si3 from an electronic structure point of view the density of states, charge density differences and Mul iken population were determined. The results show that the intrinsic brittleness of D88-Ti5Si3 comes from strong covalent bonding between Ti6g and Si6g. When one or two Ti atoms occupy Si sites in the D88-Ti5Si3 crystal the intensity of covalent bonding between Ti6g and Si6g is reduced and the metal icity increases. This is accompanied by the presence of low intensity Al6g―Si6g, Ti6g―Al6g, and Ti4d―Al6g bonds. However, when three Ti atoms occupy Si sites in the D88-Ti5Si3 crystal the Al6g―Si6g bonds disappear and the intensity of covalent bonding between Ti6g and Si6g increases leading to an increase in brittleness.关键词
第一性原理/钛硅化合物/化学键/韧/脆性/电子结构Key words
First-principles/Titanium-silicon compound/Chemical bond/Ductile/brittle behavior/Electronic structure分类
化学化工引用本文复制引用
黄豪杰,徐江..Al代位合金化对D88-Ti5Si3力学性能与电子结构影响的第一性原理研究[J].物理化学学报,2015,(2):253-260,8.基金项目
The project was supported by the National Natural Science Foundation of China (51374130) and Aeronautical Science Foundation of China (2013ZE52058).国家自然科学基金(51374130)和航空科学基金(2013ZE52058)资助项目 （51374130）
