不同荷载作用下二维硼烯的力学性能及变形破坏机理  

Mechanical properties and deformation mechanisms of two-dimensional borophene under different loadings

作　　者：韩同伟[1] 李选政 赵泽若 顾叶彤 马川 张小燕[2] Han Tong-Wei;Li Xuan-Zheng;Zhao Ze-Ruo;Gu Ye-Tong;Ma Chuan;Zhang Xiao-Yan(Faculty of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang 212013,China;School of Chemistry and Chemical Engineering,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]江苏大学土木工程与力学学院,镇江212013 [2]江苏大学化学化工学院,镇江212013

出　　处：《物理学报》2024年第11期251-262,共12页Acta Physica Sinica

基　　金：江苏省高等学校自然科学研究重大项目(批准号:17KJA130001)资助的课题。

摘　　要：二维硼烯具有丰富的物理和化学性质,在凝聚态物理和材料科学等领域引起了广泛的研究兴趣,但硼烯在不同荷载作用下的力学性能和变形破坏机理仍需进一步研究.本文采用分子动力学方法模拟了硼烯的拉伸、剪切和纳米压痕破坏过程,获得了硼烯的关键力学性能参数,并从两种不同类型的B—B键长随应变/压入深度的变化规律分析了硼烯在不同载荷作用下的力学性能和变形破坏机理.研究发现,硼烯的拉伸力学性能表现出显著的各向异性特性,沿扶手椅方向的杨氏模量和强度远高于沿锯齿方向,而硼烯的剪切力学性能的各向异性特性不明显,产生以上现象的原因可归因于强σ键B—B键和弱多中心键的不同贡献.研究还发现,硼烯在球形和圆柱形压头载荷作用下表现出不同的力学响应规律.在球形压头载荷作用下,硼烯能承受的最大压入载荷远低于圆柱形压头的情况,而且无法测得与拉伸一致的本征力学性能参数,而采用圆柱形压头沿不同的方向压入硼烯薄膜时,硼烯也表现出与拉伸时类似的各向异性特性,并且可以测得与拉伸时一致的杨氏模量等力学性能参数.本文还研究了压痕模型尺寸与压头半径的比值、压头加载速率和加载温度等因素对硼烯力学性能参数的影响规律.以上研究结果可为基于硼烯的微/纳米机电系统的实际应用提供重要指导.Two-dimensional(2D)borophene has attracted widespread research interest in condensed matter physics and materials science because of its rich physical and chemical properties.However,the mechanical properties and deformation mechanisms of borophene under different loadings are still unclear and not thoroughly investigated.In this work,the tensile,shear,and nanoindentation failure processes of borophene are simulated via molecular dynamics method to obtain the key mechanical parameters of borophene.The mechanical response and deformation mechanism of borophene under different loads are analyzed from the change of B-B bond length with the strain/indentation depth.The results show that the tensile mechanical properties of borophene exhibit significant anisotropic characteristics,with the Young’s modulus and strength along the armchair direction being much higher than those along the zigzag direction.However,the anisotropy of the shear mechanical properties of borophene is not significant.This phenomenon can be attributed to the different contributions of the strong B-Bσbonds and weak multi-center bonds in borophene when they are stretched in different directions.It is also found that borophene exhibits different mechanical responses under spherical indentation and cylindrical indentation.The force at failure of the borophene under spherical indentation is much lower than the value under cylindrical one,and the intrinsic mechanical parameters of borophene under spherical indentation cannot be estimated accurately because of the anisotropic characteristics of borophene.However,under cylindrical indentation,borophene exhibits similar anisotropic characteristics to those under tension,and the mechanical parameters such as Young’s modulus can be measured accurately,which are consistent with those obtained under tension.In addition,the effects of the borophene indentation model and spherical/cylindrical indenter size,the loading rate and temperature on the mechanical parameters of borophene are also studied systemati

关 键 词：硼烯 力学性能 变形机理 分子动力学 

分 类 号：TG1[金属学及工艺—金属学]