Effect of strain rate on tensile strength of defective silicon nanorods  

作　　者：Tao Chen Ran Xu Qingbin Li 

机构地区：[1]Beijing MTR Construction Administration Corporation [2]AML, Department of Engineering Mechanics, Tsinghua University [3]State Key Laboratory of Hydroscience and Engineering, Tsinghua University

出　　处：《Acta Mechanica Solida Sinica》2015年第2期133-144,共12页固体力学学报（英文版）

基　　金：supported by National Basic Research Program of China(No.2013CB035902);Research Project of State Key Laboratory of Hydroscience and Engineering of Tsinghua University(No.2011-KY-4);the National Natural Science Foundation of China(Nos.51339033 and 51279087)

摘　　要：The effect of strain rate on the tensile strength of defective monocrystalline silicon （Si） nanorods is studied with the molecular dynamics method. The strain rate applied to the nanorods is varied from l0T to 1014 s-1, and the atomic interactions among the Si atoms are described by the Stillinger-Weber （SW） potential functions. The tensile strength of the ideal Si nanorod is shown to be strongly strain rate dependent and increasing with the strain rate. The failure pattern also shows strain rate dependence, indicating that increased strain rates gradually suppress unsuitable relaxation and dissipation mechanisms because of the accompanying larger external loadings. Furthermore, the effects of intrinsic material parameters （i.e., the cutoff radius of SW potential function） and defects （i.e., inevitable surface defects and internal preinstalled defects） are investigated. It is revealed that the effect of strain rate on the tensile strength of Si nanorod is influenced by both the intrinsic physical properties of the material and the distribution of the initial defects, with specific surface defects appearing to be more important to nanostructure design.The effect of strain rate on the tensile strength of defective monocrystalline silicon （Si） nanorods is studied with the molecular dynamics method. The strain rate applied to the nanorods is varied from l0T to 1014 s-1, and the atomic interactions among the Si atoms are described by the Stillinger-Weber （SW） potential functions. The tensile strength of the ideal Si nanorod is shown to be strongly strain rate dependent and increasing with the strain rate. The failure pattern also shows strain rate dependence, indicating that increased strain rates gradually suppress unsuitable relaxation and dissipation mechanisms because of the accompanying larger external loadings. Furthermore, the effects of intrinsic material parameters （i.e., the cutoff radius of SW potential function） and defects （i.e., inevitable surface defects and internal preinstalled defects） are investigated. It is revealed that the effect of strain rate on the tensile strength of Si nanorod is influenced by both the intrinsic physical properties of the material and the distribution of the initial defects, with specific surface defects appearing to be more important to nanostructure design.

关 键 词：strain rate DEFECT Si nanorod tensile strength molecular dynamics 

分 类 号：TN304.12[电子电信—物理电子学] TB383.1[一般工业技术—材料科学与工程]