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Transmission electron microscopy of materials
01 Jan 1979-
About: The article was published on 1979-01-01 and is currently open access. It has received 397 citations till now. The article focuses on the topics: Energy filtered transmission electron microscopy & Scanning confocal electron microscopy.
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01 Sep 2002-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, a tensile strength of 0.15 TPa was computed for individual carbon nanotubes in-situ in a transition electron microscope, based on the force required to break the tube.
Abstract: We have conducted pulling and bending tests on individual carbon nanotubes in-situ in a transition electron microscope. Based on our observation of the force required to break the tube, a tensile strength of 0.15 TPa was computed. From corresponding bending studies on such nanotubes, the Young's modulus was estimated to be 0.9 TPa (0.8 TPa after ‘sub continuum’ corrections). These results suggest a strength that is a large fraction of the elastic modulus, although previous measurements of their elastic stiffness have yielded higher modulus values, by as much as a factor of 2. The result does indicate that individual nanotubes can fail as essentially defect-free materials. Furthermore, we observed no obvious reduction in cross-sectional area prior to the failure. In addition, the bending experiments revealed a remarkable flexibility in these tubes. These unique properties support the potential of nanotubes as reinforcement fibers in structural materials.
1,069 citations
Cites background from "Transmission electron microscopy of..."
...This contrast arises due to a bending of atomic planes, which deflect the electron beam away locally [33]....
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TL;DR: In this paper, a classification scheme for implant-related damage which arise upon annealing consisting of five categories is presented, and the most common forms of this damage are microtwins, hairpin dislocations and segregation related defects.
Abstract: A classification scheme for the different forms of implant-related damage which arise upon annealing consisting of five categories is presented. Category I damage is “subthreshold” damage or that which results prior to the formation of an amorphous layer. If the dose is increased sufficiently to result in the formation of an amorphous layer then the defects which form beyond the amorphous/crystalline (a/c) interface are classified as category II (“end of range”) damage. Category III defects are associated with the solid phase epitaxial growth of the amorphous layer. The most common forms of this damage are microtwins, hairpin dislocations and segregation related defects. It is possible to produce a buried amorphous layer upon implantation, If this occurs, then the defects which form when the two a/c interfaces meet are termed category IV (“clamshell”, “zipper”) defects. Finally, category V defects arise from exceeding the solid solubility of the implanted species in the substrate at the annealing temperature. These defects are most often precipitates or dislocation loops.
478 citations
31 Oct 1998-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, a 304 type austenitic stainless steel was studied in connection with microstructural developments in compression at temperatures of 873 −1223 K (0.5 −0.7 Tm) under strain rates of 10−4 −10−1s−1.
Abstract: Warm (and hot) deformation of a 304 type austenitic stainless steel was studied in connection with microstructural developments in compression at temperatures of 873–1223 K (0.5–0.7 Tm) under strain rates of 10−4–10−1s−1. The two deformation domains can be categorized due to their different mechanical and microstructural behaviors. In the region of flow stresses lower than around 400 MPa, the deformation behaviors are typical for hot working accompanied with dynamic recrystallization (DRX). New grains are evolved mainly by dynamic bulging mechanism, which can be accelerated by the development of serrated grain boundaries and strain induced dislocation subboundaries. The relationship between dynamic grain sizes ranged from 2 to 7 μm and peak flow stress can be expressed by a power law function with a grain size exponent of −0.72. In contrast, in the region of flow stresses higher than 400 MPa, the deformation behaviors hardly depend on strain rate and temperature and so can be in the region of athermal deformation. The stress–strain curves under such warm deformation are similar to those affected only by dynamic recovery. The microstructures evolved at high strains are mainly characterized by the dense dislocation walls evolved in pancaked original grains, while grain boundary serration also takes place even at such warm deformation. Mechanisms of this microstructural evolution are discussed in combination with analysis of deformation mechanisms operating under warm deformation.
198 citations
TL;DR: An electron microscopy characterization of the melt-spun MAGNEQUENCH magnet as discussed by the authors showed that the best magnetic properties are obtained in materials with a two-phase microstructure where 20-30 nm size Nd 2 Fe 14 B grains are completely surrounded by a 1-2 nm thick amorphous film of Nd rich and B deficient phase.
168 citations
TL;DR: In this paper, microstructural observation and thermal analysis of Al-21 wt % Si alloys with different rare earth metals were performed to examine the effect of rare earth metal on the refinement of primary silicon phase.
Abstract: Microstructural observation and thermal analysis of Al-21 wt % Si alloys with different rare earth metals were performed to examine the effect of rare earth metal on the refinement of primary silicon phase. Simultaneous refinement of both primary and eutectic silicon morphology is achieved with the addition of rare earth and its effect increases with the amount of rare earth addition and cooling rate. Depression of 12–17 °C in primary reaction temperature and 2–7 °C in eutectic temperature is measured with the addition of rare earth. Rare earth bearing compounds were not believed to act as a nucleation agent of primary silicon phase. Some rare earth bearing compounds determined to AlCe were around primary silicon in the matrix. The twin density of eutectic silicon remains same regardless of the addition of rare earth. The refinement of silicon in rare earth treated hypereutectic Al-Si alloys is supposed to be due to the suppression of the nucleation temperature of silicon phase.
153 citations