Size Effects on Mechanical Properties of Silver Nanowires
Yong Zhu (North Carolina State University), Qingquan Qin (), Guangming Cheng (), Feng Xu ()
Synthesis, Characterization, and Modeling of Low-Dimensional Nanomaterials
Wed 10:45 - 12:15
Salomon 202
We present a full spectrum of mechanical properties of ve-fold twinned silver (Ag) nanowires (NWs), including Young’s modulus, yield strength, and ultimate tensile strength. In-situ tensile testing of Ag NWs with diameters between 34 and 130 nm was carried out inside a scanning electron microscope (SEM). Young’s modulus, yield strength, and ultimate tensile strength all increased as the NW diameter decreased. The maximum yield strength in our tests was found to be 2.64 GPa, which is about 50 times the bulk value and close to the theoretical value of Ag in the < 110 > orientation. The size effect in the yield strength is mainly due to the stiffening size effect in the Young’s modulus. Yield strain scales reasonably well with the NW surface area, which reveals that yielding of Ag NWs is due to dislocation nucleation from surface sources. Pronounced strain hardening was observed for most NWs in our study. The strain hardening, which has not previously been reported for NWs, is mainly attributed to the presence of internal twin boundaries.