The Experts below are selected from a list of 36138 Experts worldwide ranked by ideXlab platform
Tobin Filleter - One of the best experts on this subject based on the ideXlab platform.
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Local straIn mappIng of GO nanosheets under In Situ TEM tensile testIng
Applied Materials Today, 2019Co-Authors: Changhong Cao, Tobin Filleter, Zhuoran Zhang, Maedeh Amirmaleki, Jason Tam, Wenkun Dou, Yu SunAbstract:Abstract Local straIn mappIng of 2D materials at nanoscale under contInuous deformation can enable a variety of studies on 2D materials IncludIng but not limited to more accurate characterization of physical properties, heterogeneity characterization of functionalized 2D materials, and straIn engIneerIng of 2D materials. Here, usIng graphene oxide (GO) as a representative material, we report a technique that achieves local straIn mappIng of 2D materials at nanoscale through gold nanoparticle decoration over GO under In Situ TEM tensile testIng and imagIng. Our results reveal that GO at different uniaxial tensile straIn levels exhibits a heterogeneous local straIn distribution. UsIng this technique, the permanent deformation of GO was also quantified to be ∼1% on average. The technique can be readily applied to the straIn mappIng of other 2D materials.
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In Situ TEM electromechanical testIng of nanowires and nanotubes
Small, 2012Co-Authors: Horacio D Espinosa, Rodrigo A Bernal, Tobin FilleterAbstract:The emergence of one-dimensional nanostructures as fundamental constituents of advanced materials and next-generation electronic and electromechanical devices has Increased the need for their atomic-scale characterization. Given its spatial and TEMporal resolution, coupled with analytical capabilities, transmission electron microscopy (TEM) has been the technique of choice In performIng atomic structure and defect characterization. A number of approaches have been recently developed to combIne these capabilities with In-Situ mechanical deformation and electrical characterization In the emergIng field of In-Situ TEM electromechanical testIng. This has enabled researchers to establish unambiguous synthesis-structure-property relations for one-dimensional nanostructures. In this article, the development and latest advances of several In-Situ TEM techniques to carry out mechanical and electromechanical testIng of nanowires and nanotubes are reviewed. Through discussion of specific examples, it is shown how the mergIng of several microsysTEMs and TEM has led to significant Insights Into the behavior of nanowires and nanotubes, underscorIng the significant role In-Situ techniques play In the development of novel nanoscale sysTEMs and materials.
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Nano and Cell Mechanics: Fundamentals and Frontiers - In Situ TEM Electromechanical TestIng of Nanowires and Nanotubes
Small (Weinheim an der Bergstrasse Germany), 2012Co-Authors: Horacio D Espinosa, Rodrigo A Bernal, Tobin FilleterAbstract:The emergence of one-dimensional nanostructures as fundamental constituents of advanced materials and next-generation electronic and electromechanical devices has Increased the need for their atomic-scale characterization. Given its spatial and TEMporal resolution, coupled with analytical capabilities, transmission electron microscopy (TEM) has been the technique of choice In performIng atomic structure and defect characterization. A number of approaches have been recently developed to combIne these capabilities with In-Situ mechanical deformation and electrical characterization In the emergIng field of In-Situ TEM electromechanical testIng. This has enabled researchers to establish unambiguous synthesis-structure-property relations for one-dimensional nanostructures. In this article, the development and latest advances of several In-Situ TEM techniques to carry out mechanical and electromechanical testIng of nanowires and nanotubes are reviewed. Through discussion of specific examples, it is shown how the mergIng of several microsysTEMs and TEM has led to significant Insights Into the behavior of nanowires and nanotubes, underscorIng the significant role In-Situ techniques play In the development of novel nanoscale sysTEMs and materials.
Javier Llorca - One of the best experts on this subject based on the ideXlab platform.
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Tensile deformation and fracture mechanisms of Cu/Nb nanolamInates studied by In Situ TEM mechanical tests
Extreme Mechanics Letters, 2018Co-Authors: Miguel A. Monclús, Miguel Castillo-rodríguez, L W Yang, Jon Mikel Molina-aldareguia, Javier LlorcaAbstract:Abstract The mechanisms of deformation and failure of Cu/Nb nanolamInates manufactured by accumulated roll bondIng were analysed usIng In-Situ TEM mechanical tests. Dog-bone small-scale tensile specimens were prepared usIng a FIB-based technique with the layers parallel and perpendicular to the loadIng axis. Load, deformation and TEM micrographs were recorded durIng the In-Situ TEM mechanical tests. The specimens deformed parallel to the layers presented very high straIn hardenIng and ductility while those deformed In the perpendicular orientation were more brittle. These results were rationalized In terms of the deformation and fracture mechanisms observed durIng the tests.
Andrew M. Minor - One of the best experts on this subject based on the ideXlab platform.
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In Situ TEM observation of FCC Ti formation at elevated TEMperatures
Scripta Materialia, 2017Co-Authors: Josh Kacher, Christoph Gammer, Rachel Traylor, Amit Samanta, Zhenzhong Yang, Andrew M. MinorAbstract:Abstract Pure Ti traditionally exhibits the hexagonal closed packed (HCP) crystallographic structure under ambient conditions and the body centered cubic (BCC) structure at elevated TEMperatures. In addition to these typical structures for Ti alloys, the presence of a face centered cubic (FCC) phase associated with thIn films, Interfaces, or high levels of plastic deformation has occasionally been reported. Here we show that small FCC precipitates form In freestandIng thIn foils durIng In Situ transmission electron microscope (TEM) heatIng and we discuss the potential origIns of the FCC phase In light of the In Situ observations. This FCC phase was found to be stable upon coolIng and under ambient conditions, which allowed us to explore its mechanical properties and stability via nanomechanical In Situ TEM testIng. It was found that FCC platelets withIn the HCP matrix phase were stable under mechanical deformation and exhibited similar mechanical deformation behavior as the parent HCP phase.
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In Situ TEM Nanomechanical TestIng
MEMS and Nanotechnology Volume 5, 2016Co-Authors: Josh Kacher, Claire Chisholm, Christoph Gammer, Andrew M. MinorAbstract:CorrelatIng the mechanical behavior of metals with the underlyIng defect mechanisms remaIns an outstandIng challenge for the development of new material sysTEMs. In Situ Transmission Electron Microscopy (TEM) nanomechanical testIng provides an experimental technique whereby the behavior of defects such as dislocations and twIns can be observed In real time while quantitatively correlatIng their behavior with an applied stress. This paper highlights recent experiments utilizIng In Situ TEM testIng to Investigate the behavior of twIns and dislocations In FCC, BCC, and HCP materials. Examples of recently developed experimental approaches and future directions of In Situ TEM nanomechanical testIng are presented.
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In Situ TEM nanocompression testIng
EMC 2008 14th European Microscopy Congress 1–5 September 2008 Aachen Germany, 1Co-Authors: Andrew M. Minor, R. K. MishraAbstract:Recent progress In small-scale mechanical testIng methods has greatly improved our understandIng of size effects In volumes of a few nanometers to a few microns [1–5]. Besides the important results related to the effect of size on the strength of small structures, the ability to sysTEMatically measure the mechanical properties of small volumes of material allows us to test samples that cannot easily be processed In bulk form. Recently, we have used a quantitative In Situ TEM mechanical testIng device to compress microfabricated pillars Inside a TEM so that we can make a direct correlation between an imposed stress and an Individual deformation event.
Olivier N. Pierron - One of the best experts on this subject based on the ideXlab platform.
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In Situ TEM measurement of activation volume In ultrafIne graIned gold.
Nanoscale, 2020Co-Authors: Saurabh Gupta, Josh Kacher, Ting Zhu, Sandra Stangebye, Katherine L. Jungjohann, Brad L. Boyce, Olivier N. PierronAbstract:A micro-electromechanical sysTEM (MEMS) based technique is demonstrated for In Situ transmission electron microscopy (TEM) measurements of stress relaxation with simultaneous observation of the underlyIng plastic deformation processes. True activation volumes are determIned from repeated stress relaxation transients and thus provide a signature parameter of the governIng mechanisms of plastic deformation. The technique is demonstrated with 100 nm-thick ultrafIne-graIned gold microspecimens under uniaxial tension. True activation volumes of approximately 3–5b3 (where b is the Burgers vector length) are obtaIned for tensile stresses rangIng from 200–450 MPa. GraIn boundary-dislocation Interactions are observed via In Situ TEM durIng stress relaxation measurements. The mIniaturization of stress relaxation tests Inside the TEM provides unique opportunities to characterize the plastic kInetics and underlyIng mechanisms In ultrafIne-graIned and nanocrystallIne materials.
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IntegratIng In Situ TEM experiments and atomistic simulations for defect mechanics
Current Opinion in Solid State and Materials Science, 2019Co-Authors: Josh Kacher, Ting Zhu, Olivier N. Pierron, Douglas E. SpearotAbstract:Abstract With recent advances In computational modelIng and In Situ transmission electron microscopy (TEM) technologies, there have been Increased efforts to apply these approaches to understand defect-based mechanisms dictatIng deformation mechanics. In Situ TEM experiments and atomistic simulations each have their own unique limitations, IncludIng observable length and time scales and accessibility of Information, motivatIng approaches that combIne the two approaches. In this paper, we review recent studies that combIne atomistic simulations and In Situ TEM experiments to understand defect mechanisms associated with deformation of metals and alloys. In addition, we discuss ongoIng developments In characterization and simulation capabilities that are expected to significantly advance the field of defect mechanics and allow greater Integration between atomistic simulations and In Situ TEM experiments.
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Correction: Quantitative In Situ TEM tensile fatigue testIng on nanocrystallIne metallic ultrathIn films.
Nanoscale, 2015Co-Authors: Ehsan Hosseinian, Olivier N. PierronAbstract:Correction for ‘Quantitative In Situ TEM tensile fatigue testIng on nanocrystallIne metallic ultrathIn films’ by Ehsan HosseInian, et al., Nanoscale, 2013, 5, 12532–12541.
Guo Jin - One of the best experts on this subject based on the ideXlab platform.
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Fracture behavior of high-entropy alloy coatIng by In-Situ TEM tensile testIng
Journal of Alloys and Compounds, 2017Co-Authors: Zhaobing Cai, Xiufang Cui, Erbao Liu, Meiling Dong, Guo JinAbstract:Abstract The fracture behavior of high-profile high-entropy alloy coatIng was characterized by In-Situ TEM tensile testIng. The samples for In-Situ TEM tensile testIng were obtaIned by FIB technology. The results show that irrelevant to phase constitution, the Young's module, fracture strength and ultimate elongation are measured as ∼107 GPa, ∼2.70 GPa and ∼2.6%, respectively. TranscrystallIne fracture and cleavage fracture with the cleavage plane of {112} are observed evidentially and the evolution of the dislocation motion In the material could be directly connected with the fracture behavior from the recorded movies obtaIned by a Gatan CCD camera. The engIneerIng stress-straIn curve is nearly lInearity, however, a slight deviation away from lInearity could be noted In the end of engIneerIng stress-straIn curve, which is attributed that the extra elastic deformation results In part of contInued deformation.
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In Situ TEM tensile testIng on high-entropy alloy coatIng by laser surface alloyIng
Journal of Alloys and Compounds, 2017Co-Authors: Zhaobing Cai, Xiufang Cui, Guo Jin, Danli Zhang, Zhanming ZhangAbstract:Abstract A unique technique, In Situ TEM tensile testIng, was used to Investigate the fracture process of Ni-Cr-Co-Ti-V-Al high-entropy alloy coatIng with complex phases. The results of In Situ TEM observation Indicated that durIng the fracture process, dislocations get together In the Interface between BCC HEA phase and (Co, Ni)Ti 2 compounds and crack propagation happens along the phase Interface, leadIng to the fInal rupture, which proves that the phase Interface may be the probable failure place. Also, the fracture strength and Young's modulus were calculated accordIng to the stress-straIn curve from the In Situ TEM tensile testIng. The stress-straIn curve shows a good lInearity, confirmIng the brittle failure. The fracture strength is calculated to be ∼3.3 GPa and the fracture straIn is measured to be ∼3.1%. The Young's modulus of the tensile sample is calculated to be ∼102 GPa, quite close to that of bulk titanium alloy.
