This paper aims to obtain the simple closed-form results for the combined effects of surface elasticity, initial stress/ strain, and material Poisson ratio on the bending stiffness, natural frequency and buckling forc...This paper aims to obtain the simple closed-form results for the combined effects of surface elasticity, initial stress/ strain, and material Poisson ratio on the bending stiffness, natural frequency and buckling force of nanowires and nano-plates. The results demonstrate that all these properties of nanowires or nanoplates can be designed either very sensitive or not sensitive at all to the amplitude of an applied electric potential;show how much of those properties can be controlled to vary;and thus provide a reliable guide to the measurement of the Young’s modulus of nanowires/nanoplates and to the design of nano-devices, such as nano-sensors or the cantilever of an AFM.展开更多
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 quantitie...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.展开更多
文摘This paper aims to obtain the simple closed-form results for the combined effects of surface elasticity, initial stress/ strain, and material Poisson ratio on the bending stiffness, natural frequency and buckling force of nanowires and nano-plates. The results demonstrate that all these properties of nanowires or nanoplates can be designed either very sensitive or not sensitive at all to the amplitude of an applied electric potential;show how much of those properties can be controlled to vary;and thus provide a reliable guide to the measurement of the Young’s modulus of nanowires/nanoplates and to the design of nano-devices, such as nano-sensors or the cantilever of an AFM.
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)+1 种基金Eu-FP7 Project(No.247644)CAS Strategy Pilot Program(No.XRA 09020300).
文摘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.
