【摘要】 弹性性能是材料最基本的力学性能之一。随着样品尺寸减小,纳米材料(如纳米线)的弹性模量可能偏离块体材料的值,而其准确测量是认识这一尺寸效应的前提。本文基于自行设计制作的纳米操纵台和纳米压电马达,讨论了在扫描电镜中原位测量纳米线弹性模量的两种主要方法,即电致振动和单轴拉伸方法。通过分析电致振动模式,确立了纳米线固有频率的判定准则,从而保证了弯曲模量的准确测量;通过建立包含五个运动自由度的测量系统,并选择合适的加载悬臂,实现了拉伸模量的准确测量。更多还原

【Abstract】 Elastic modulus is one of the most basic mechanical properties of materials.The modulus in nanostructures,i.e.nanowires(NWs),generally differs from the bulk value,and accurate measurement of modulus plays a crucial role in theoretically understanding the elasticity in nanoscale.Herein,the electric-field-induced-resonance method and uniaxial tensile testing,utilizing the home-made nanomanipulator and nanopiezomotor in scanning electron microscope,are investigated.First,identifying criterion for the natural frequency of NWs is achieved by analyzing the resonance modes,the bending moduli of NWs are thus accurately determined.Moreover,based on the testing system containing five degrees of freedom and an appropriate loading cantilever,the tensile moduli of NWs can be accurately measured.更多还原