Multiphysics design and implementation of a microsystem for displacement-controlled tensile testing of nanomaterials

Pantano, Maria F.; Bernal, Rodrigo A.; Pagnotta, Leonardo; Espinosa, Horacio D.

doi:10.1007/s11012-014-9950-9

Cited by 28 publications

(21 citation statements)

References 39 publications

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“…Previous tensile testing results reported on nanowires have been obtained under loading conditions that are neither strictly load controlled nor displacement controlled. ,,, In this work, we use a recently developed low-noise, high-resolution MEMS-based testing system capable of testing nanowires in displacement control . This testing device uses a thermal actuator with chevron shaped beams, which when subjected to a particular input voltage displaces the shuttle where one end of the nanowire is mounted.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, the displacement applied by the thermal actuator equals the displacement of the nanowire and the load applied on the nanowire can be obtained from the electrostatic force applied using the actuation fingers. A brief description and working of this tensile testing device under displacement control is given in the Methods/Experimental Section and a more detailed description is provided elsewhere. , It should be noted that the projected width of the nanowires were measured from the SEM/TEM images, as shown in Figure S6. Given that we do not have the capability to rotate the nanowires, this width was used as the diameter of the circumcircle around the distorted hexagonal shape of the nanowire.…”

Section: Resultsmentioning

confidence: 99%

“…9,11,12,18 In this work, we use a recently developed low-noise, high-resolution MEMS-based testing system capable of testing nanowires in displacement control. 14 This testing device uses a thermal actuator with chevron shaped beams, which when subjected to a particular input voltage displaces the shuttle where one end of the nanowire is mounted. The other end of the nanowire is mounted on a flexible load sensing shuttle.…”

Section: Resultsmentioning

confidence: 99%

“…For the most part, the metallic nanowires have been tested only in load control under monotonic loading conditions, at quasi-static − and high strain rates . Due to the experimental complexity, only a few nanowire tests have been conducted under displacement control. , …”

mentioning

confidence: 99%

“…9 Due to the experimental complexity, only a few nanowire tests have been conducted under displacement control. 10,14 There have been several reports on the size-dependent mechanical properties of nanowires, while only a very few studies have been reported on their time-dependent mechanical behavior. One of the reasons for the lack of time-dependent nanomechanical tests is the requirement to have stable MEMSbased testing platforms capable of outputting electrical signals without significant time-dependent drift.…”

mentioning

confidence: 99%

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Reliability of Single Crystal Silver Nanowire-Based Systems: Stress Assisted Instabilities

et al. 2017

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Time-dependent mechanical characterization of nanowires is critical to understand their long-term reliability in applications, such as flexible-electronics and touch screens. It is also of great importance to develop a theoretical framework for experimentation and analysis on the mechanics of nanowires under time-dependent loading conditions, such as stress-relaxation and fatigue. Here, we combine in situ scanning electron microscope (SEM)/transmission electron microscope (TEM) tests with atomistic and phase-field simulations to understand the deformation mechanisms of single crystal silver nanowires held under constant strain. We observe that the nanowires initially undergo stress-relaxation, where the stress reduces with time and saturates after some time period. The stress-relaxation process occurs due to the formation of few dislocations and stacking faults. Remarkably, after a few hours the nanowires rupture suddenly. The reason for this abrupt failure of the nanowire was identified as stress-assisted diffusion, using phase-field simulations. Under a large applied strain, diffusion leads to the amplification of nanowire surface perturbation at long wavelengths and the nanowire fails at the stress-concentrated thin cross-sectional regions. An analytical analysis on the competition between the elastic energy and the surface energy predicts a longer time to failure for thicker nanowires than thinner ones, consistent with our experimental observations. The measured time to failure of nanowires under cyclic loading conditions can also be explained in terms of this mechanism.

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