Relationship between Si concentration and mechanical properties of Nb-Si compounds: A first-principles study

被引：83

作者：

Pan, Yong ^{[1
]}

Lin, Yuanhua ^{[1
]}

Xue, Qi ^{[1
]}

Ren, Chengqiang ^{[1
]}

Wang, Hu ^{[1
]}

机构：

[1] Southwest Petr Univ, Sch Mat Sci & Engn, Chengdu 610500, Peoples R China

来源：

MATERIALS & DESIGN | 2016年 / 89卷

基金：

中国国家自然科学基金;

关键词：

Transition metal suicides; Elastic behavior; Hardness; First-principles calculation; AB-INITIO; FRACTURE-TOUGHNESS; ELASTIC PROPERTIES; EUTECTIC ALLOY; BINARY-SYSTEM; HIGH-PRESSURE; MICROSTRUCTURE; TRANSITION; BEHAVIOR; COMPOSITES;

D O I：

10.1016/j.matdes.2015.10.028

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The effect of chemical bonding on the mechanical properties of high-temperature materials remains a big challenge. In this paper, the relationship between Si concentration and mechanical properties for Nb-Si compounds was investigated by first-principles calculations. One previously unreported crystal structure of Nb2Si with Ta2Si-type structure was predicted. The elastic properties, hardness and chemical bonding of Nb-Si compounds were calculated in detail. The calculated formation enthalpy shows that Nb5Si3 is more stable than that of other NbSi compounds at the ground state. The obtained shear modulus, Young's modulus and hardness of Nb-Si compounds increase with increasing Si concentration. NbSi2 exhibits the strongest shear deformation resistance and the biggest hardness among these Nb-Si compounds. It thus can be concluded that the variation of elastic properties depends not only on the Si concentration but also on the chemical bonding. With increasing Si concentration, Nb-Nb metallic bond is disappeared and Si-Si covalent bond is formed. (C) 2015 Elsevier Ltd. All rights reserved.

引用

页码：676 / 683

页数：8