Dimension-dependent mechanical features of Au-nanocrystalline nanofilms  

作　　者：Lijun Ma Lena Du Shu Wang Qing Wang Shifeng Xue Hanxing Zhu Qian Liu 

机构地区：[1]Department of Engineering Mechanics,College of Pipeline and Civil Engineering,China University of Petroleum(East China),Qingdao 266580,China [2]CAS Center for Excellence in Nanoscience,National Center for Nanoscience and Technology&University of Chinese Academy of Sciences,Beijing 100190,China [3]Department of Physics,Capital Normal University,Beijing 100048,China [4]School of Engineering,Cardiff University,Cardiff CF243AA,UK [5]MOE Key Laboratory of Weak-Light Nonlinear Photonics,TEDA Applied Physics Institute,School of Physics,Nankai University,Tianjin 300457,China [6]College of Mechanical and Architectural Engineering,Taishan University,Tai’an 271000,China

出　　处：《Nano Research》2023年第12期13400-13408,共9页纳米研究（英文版）

基　　金：supported by the National Natural Science Foundation of China(NSFC)(No.51971070);the National Key Research and Development Program of China(No.2016YFA0200403);Eu-FP7 Project(No.247644);CAS Strategy Pilot Program(No.XRA 09020300).

摘　　要：For metal nanofilms composed of nanocrystals,the multiple deformation mechanisms will coexist and bring unique and complex elastic-plastic and fracture mechanical properties.By successfully fabricating large quantities of uniform doubly-clamped suspended gold(Au)nanobeams with different thicknesses and nanograin sizes,we obtain full-spectrum mechanical features with statistical significance by combining atomic force microscopy(AFM)nanoindentation experiments,nonlinear theoretical model,and numerical simulations.The yield and breaking strengths of the Au nanobeams have a huge increase by nearly an order of magnitude compared with bulk Au and exhibit strong nonlinear effects,and the corresponding strong-yield ratio is up to 4,demonstrating extremely high strength reserve and vibration resistance.The strong-yield ratio gradually decreases with decreasing thickness,identifying a conversion of the failure type from ductile to brittle.Interestingly,the Hall–Petch relationship has been identified to be still valid at the nanoscale,and K in the equation reaches 4.8 Gpa·nm1/2,nearly twice of bulk nanocrystalline Au,which is ascribed to the coupling effect of nanocrystals and nanoscale thickness.

关 键 词：nanocrystalline Au nanobeams atomic force microscopy numerical simulations full-spectrum mechanical properties 

分 类 号：TB383[一般工业技术—材料科学与工程]