The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
J. Shin - One of the best experts on this subject based on the ideXlab platform.
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in situ bragg coherent x ray diffraction during Tensile Testing of an individual au nanowire
Journal of Applied Crystallography, 2018Co-Authors: J. Shin, S. Labat, F. Lauraux, M.-i. Richard, G. Richter, T W Cornelius, N P BlanchardAbstract:Systematic Tensile tests were performed on single defect-free 〈110〉 Au nanowires grown by physical vapor deposition while simultaneously recording three-dimensional Bragg peaks using coherent X-rays. The trajectory of three-dimensional Bragg peaks in reciprocal space during Tensile Testing allowed for measurements of the evolution of strains and rotations of the nanowire, thus sensitively uncovering the full deformation geometry of the nanowire. The transition from elastic to plastic deformation is accompanied by rotations of the nanowire as quantified by analysis of the motion of Bragg peaks, showing the importance of boundary conditions in interpreting nanoscale mechanical deformations.
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In situ Bragg coherent X-ray diffraction during Tensile Testing of an individual Au nanowire
Journal of Applied Crystallography, 2018Co-Authors: J. Shin, T. Cornelius, S. Labat, F. Lauraux, M.-i. Richard, G. Richter, N. Blanchard, D. Gianola, O. ThomasAbstract:We report on systematic single defect free Au nanowires grown by physical vapor deposition in situ Tensile tests while simultaneously recording 3D Bragg peaks using coherent X-rays. The trajectory of 3D Bragg peaks in reciprocal space during Tensile Testing allowed for measurements of the evolution of strains and rotations of the nanowire, thus sensitively uncovering the full deformation geometry of the nanowire. The transition from elastic to plastic deformation is accompanied by rotations of the nanowire as quantified by analysis of the motion of Bragg peaks, showing the importance of boundary conditions in interpreting nanoscale mechanical deformations.
M.-i. Richard - One of the best experts on this subject based on the ideXlab platform.
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in situ bragg coherent x ray diffraction during Tensile Testing of an individual au nanowire
Journal of Applied Crystallography, 2018Co-Authors: J. Shin, S. Labat, F. Lauraux, M.-i. Richard, G. Richter, T W Cornelius, N P BlanchardAbstract:Systematic Tensile tests were performed on single defect-free 〈110〉 Au nanowires grown by physical vapor deposition while simultaneously recording three-dimensional Bragg peaks using coherent X-rays. The trajectory of three-dimensional Bragg peaks in reciprocal space during Tensile Testing allowed for measurements of the evolution of strains and rotations of the nanowire, thus sensitively uncovering the full deformation geometry of the nanowire. The transition from elastic to plastic deformation is accompanied by rotations of the nanowire as quantified by analysis of the motion of Bragg peaks, showing the importance of boundary conditions in interpreting nanoscale mechanical deformations.
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In situ Bragg coherent X-ray diffraction during Tensile Testing of an individual Au nanowire
Journal of Applied Crystallography, 2018Co-Authors: J. Shin, T. Cornelius, S. Labat, F. Lauraux, M.-i. Richard, G. Richter, N. Blanchard, D. Gianola, O. ThomasAbstract:We report on systematic single defect free Au nanowires grown by physical vapor deposition in situ Tensile tests while simultaneously recording 3D Bragg peaks using coherent X-rays. The trajectory of 3D Bragg peaks in reciprocal space during Tensile Testing allowed for measurements of the evolution of strains and rotations of the nanowire, thus sensitively uncovering the full deformation geometry of the nanowire. The transition from elastic to plastic deformation is accompanied by rotations of the nanowire as quantified by analysis of the motion of Bragg peaks, showing the importance of boundary conditions in interpreting nanoscale mechanical deformations.
Horacio D. Espinosa - One of the best experts on this subject based on the ideXlab platform.
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high strain rate Tensile Testing of silver nanowires rate dependent brittle to ductile transition
Nano Letters, 2016Co-Authors: Rajaprakash Ramachandramoorthy, Rodrigo A. Bernal, Wei Gao, Horacio D. EspinosaAbstract:The characterization of nanomaterials under high strain rates is critical to understand their suitability for dynamic applications such as nanoresonators and nanoswitches. It is also of great theoretical importance to explore nanomechanics with dynamic and rate effects. Here, we report in situ scanning electron microscope (SEM) Tensile Testing of bicrystalline silver nanowires at strain rates up to 2/s, which is 2 orders of magnitude higher than previously reported in the literature. The experiments are enabled by a microelectromechanical system (MEMS) with fast response time. It was identified that the nanowire plastic deformation has a small activation volume (<10b3), suggesting dislocation nucleation as the rate controlling mechanism. Also, a remarkable brittle-to-ductile failure mode transition was observed at a threshold strain rate of 0.2/s. Transmission electron microscopy (TEM) revealed that along the nanowire, dislocation density and spatial distribution of plastic regions increase with increasin...
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Multiphysics design and implementation of a microsystem for displacement-controlled Tensile Testing of nanomaterials
Meccanica, 2015Co-Authors: Maria F. Pantano, Rodrigo A. Bernal, Leonardo Pagnotta, Horacio D. EspinosaAbstract:MEMS-based Tensile Testing devices are powerful tools for mechanical characterization of nanoscale materials. In a typical configuration, their design includes an actuator to deliver loads/displacements to a sample, and a sensing unit for load measurement. The sensing unit consists of a flexible structure, which deforms in response to the force imposed to the sample. Such deformation, while being necessary for the sensing function, may become a source of instability. When the sample experiences a load drop, as it may result from yield, necking or phase transitions, the elastic energy accumulated by the sensor can be released, thus leading to loss of the displacement-controlled condition and dynamic failure. Here, we report a newly-developed MEMS Testing system where the sensor is designed to constantly keep its equilibrium position through an electrostatic feedback-control. We show design, implementation, and calibration of the system, as well as validation by Tensile Testing of silver nanowires. The implemented system allows capture of softening events and affords significant improvement on the resolution of stress–strain curves.
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in situ transmission electron microscope Tensile Testing reveals structure property relationships in carbon nanofibers
Carbon, 2013Co-Authors: Allison M Beese, Dimitry Papkov, Shuyou Li, Yuris A Dzenis, Horacio D. EspinosaAbstract:Abstract Tensile tests were performed on carbon nanofibers in situ a transmission electron microscope (TEM) using a microelectromechanical system (MEMS) Tensile Testing device. The carbon nanofibers tested in this study were produced via the electrospinning of polyacrylonitrile (PAN) into fibers, which are subsequently stabilized in an oxygen environment at 270 °C and carbonized in nitrogen at 800 °C. To investigate the relationship between the fiber molecular structure, diameter, and mechanical properties, nanofibers with diameters ranging from ∼100 to 300 nm were mounted onto a MEMS device using nanomanipulation inside the chamber of a Scanning Electron Microscope, and subsequently tested in tension in situ a TEM. The results show the dependence of strength and modulus on diameter, with a maximum modulus of 262 GPa and strength of 7.3 GPa measured for a 108 nm diameter fiber. In particular, through TEM evaluation of the structure of each individual nanofiber immediately prior to Testing, we elucidate a dependence of mechanical properties on the molecular orientation of the graphitic structure: the strength and stiffness of the fibers increases with a higher degree of orientation of the 0 0 2 graphitic planes along the fiber axis, which coincides with decreasing fiber diameter.
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a microelectromechanical load sensor for in situ electron and x ray microscopy Tensile Testing of nanostructures
Applied Physics Letters, 2005Co-Authors: Yong Zhu, Nicolaie Moldovan, Horacio D. EspinosaAbstract:We report on the performance of a microelectromechanical system (MEMS) designed for the in situ electron and x-ray microscopy Tensile Testing of nanostructures, e.g., carbon nanotubes and nanowires. The device consists of an actuator and a load sensor with a gap in between, across which nanostructures can be placed, nanowelded, and mechanically tested. The load sensor is based on differential capacitance measurements, from which its displacement history is recorded. By determining the sensor stiffness, the load history during the Testing is obtained. We calibrated the device and examined its resolution in the context of various applications of interest. The device is the first true MEMS in which the load is electronically measured. It is designed to be placed in scanning and transmission electron microscopes and on x-ray synchrotron stages.
Tatsuo Kawabata - One of the best experts on this subject based on the ideXlab platform.
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Tensile Testing of silicon film having different crystallographic orientations carried out on a silicon chip
Sensors and Actuators A-physical, 1998Co-Authors: Kazuo Sato, Tetsuo Yoshioka, Taeko Ando, Mitsuhiro Shikida, Tatsuo KawabataAbstract:Abstract Uniaxial Tensile Testing of single-crystal silicon film was carried out on a silicon chip. A Tensile Testing system was integrated on a silicon chip. A process for fabricating a test chip containing a specimen whose Tensile axis has an arbitrary orientation was developed. The mechanical properties, such as elastic modulus and fracture strain, of silicon films having different orientations of 〈100〉, (110), and 〈111〉, are measured. The results are compared with those of bulk materials.
O. Thomas - One of the best experts on this subject based on the ideXlab platform.
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In situ Bragg coherent X-ray diffraction during Tensile Testing of an individual Au nanowire
Journal of Applied Crystallography, 2018Co-Authors: J. Shin, T. Cornelius, S. Labat, F. Lauraux, M.-i. Richard, G. Richter, N. Blanchard, D. Gianola, O. ThomasAbstract:We report on systematic single defect free Au nanowires grown by physical vapor deposition in situ Tensile tests while simultaneously recording 3D Bragg peaks using coherent X-rays. The trajectory of 3D Bragg peaks in reciprocal space during Tensile Testing allowed for measurements of the evolution of strains and rotations of the nanowire, thus sensitively uncovering the full deformation geometry of the nanowire. The transition from elastic to plastic deformation is accompanied by rotations of the nanowire as quantified by analysis of the motion of Bragg peaks, showing the importance of boundary conditions in interpreting nanoscale mechanical deformations.
