Observation of dislocations in dynamically loaded Cu-SiO2

Volume Fraction ◽

Screw Dislocations ◽

Spherical Inclusions ◽

Transmission Electron ◽

Crystal Dispersion ◽

Strain Rate Loading

The effect of varying the strain rate loading conditions in compression on a copper single crystal dispersion-hardened with SiO2 particles has been examined. These particles appear as small spherical inclusions in the copper lattice and have a volume fraction of 0.6%. The structure of representative crystals was examined prior to any testing on a transmission electron microscope (TEM) to determine the nature of the dislocations initially present in the tested crystals. Only a few scattered edge and screw dislocations were viewed in those specimens.

Reconstruction of electron holograms recorded in a non-FEG, non-biprism TEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100139469 ◽

1995 ◽

Vol 53 ◽

pp. 618-619

Author(s):

Z.L. Wang

Keyword(s):

Electron Microscope ◽

Single Crystal ◽

Experimental Technique ◽

The Other ◽

Electron Holography ◽

Transmission Electron ◽

Coherent Sources ◽

Imaging Theory ◽

Normal Specimen

An experimental technique for performing electron holography using a non-FEG, non-biprism transmission electron microscope (TEM) has been introduced by Ru et al. A double stacked specimens, one being a single crystal foil and the other the specimen, are loaded in the normal specimen position in TEM. The single crystal, which is placed onto the specimen, is responsible to produce two beams that are equivalent to two virtual coherent sources illuminating the specimen beneath, thus, permitting electron holography of the specimen. In this paper, the imaging theory of this technique is described. Procedures are introduced for digitally reconstructing the holograms.

Development of a Mach-Zehnder type electron interferometer on a 1.2-MV field-emission transmission electron microscope

Microscopy ◽

10.1093/jmicro/dfaa040 ◽

2020 ◽

Vol 69 (6) ◽

pp. 411-416

Author(s):

Tetsuya Akashi ◽

Yoshio Takahashi ◽

Ken Harada

Keyword(s):

Electron Microscope ◽

Single Crystal ◽

Single Crystals ◽

Field Emission ◽

Beam Splitters ◽

Interference Fringes ◽

Transmission Electron ◽

Performance Results

Abstract We have developed an amplitude-division type Mach-Zehnder electron interferometer (MZ-EI). The developed MZ-EI is composed of single crystals corresponding to amplitude-division beam splitters, lenses corresponding to mirrors and an objective aperture. The spacings and azimuth angles of interference fringes can be controlled by single crystal materials and their orientations and by diffraction spots selected by the objective aperture. We built the MZ-EI on a 1.2-MV field-emission transmission electron microscope and tested its performance. Results showed that interference fringes were created for various spacings and azimuth angles, which demonstrates the practicability of the MZ-EI as an amplitude-division type electron interferometer.

Formation and evolution of porosity during high temperature creep of a nickel-based single crystal superalloy

E3S Web of Conferences ◽

10.1051/e3sconf/202015501005 ◽

2020 ◽

Vol 155 ◽

pp. 01005

Author(s):

Weiwei Liu ◽

Yuanyuan Guo ◽

Mai Zhang ◽

Jian Zhang

Keyword(s):

Electron Microscope ◽

High Temperature ◽

Single Crystal ◽

Volume Fraction ◽

Great Influence ◽

Single Crystal Superalloy ◽

Creep Process ◽

Steady Creep ◽

Transmission Electron ◽

Formation And Evolution

A Re-containing single-crystal superalloy was used to research the high temperature low stress creep behavior. Transmission electron microscope, scanning electron microscope and some other research methods are employed. The results and analysis are summarized below: Two mechanisms for the steady creep are found in this experiment. The volume fraction of pores after creep test at 1100°C increased more than 2 times compared with that before test, but the increasing at 1000°C is relatively small, which reveals that temperature has an great influence on the formation of pore during creep; There are two types of pores associated with fracture during the creep process. One is the casting shrinkage located between the interdentritic, which is formed in the solidification of the alloy. Another type of pore is nucleated and growing during the creep deformation.

Cross‐section transmission electron microscope observations of diamond‐turned single‐crystal Si surfaces

Applied Physics Letters ◽

10.1063/1.112633 ◽

1994 ◽

Vol 65 (20) ◽

pp. 2553-2555 ◽

Cited By ~ 50

Author(s):

Takayuki Shibata ◽

Atsushi Ono ◽

Kenji Kurihara ◽

Eiji Makino ◽

Masayuki Ikeda

Keyword(s):

Electron Microscope ◽

Single Crystal ◽

Cross Section ◽

Observation of Fatigue Fracture Origin in Single Crystal Silicon by Transmission Electron Microscope

The Proceedings of Mechanical Engineering Congress Japan ◽

10.1299/jsmemecj.2017.j2210102 ◽

2017 ◽

Vol 2017 (0) ◽

pp. J2210102

Author(s):

Hayato IZUMI ◽

Toshifumi KITA ◽

Shigeo ARAI ◽

Kastuhiro SASAKI ◽

Shoji KAMIYA

Keyword(s):

Electron Microscope ◽

Single Crystal ◽

Fatigue Fracture ◽

Single Crystal Silicon ◽

Crystal Silicon ◽

Fracture Origin ◽

Radiation Effects in Zircon, Hafnon, and Thorite: Implications for Pu Disposal

MRS Proceedings ◽

10.1557/proc-540-395 ◽

1998 ◽

Vol 540 ◽

Cited By ~ 1

Author(s):

A. Meldrum ◽

S.J. Zinkle ◽

L.A. Boatner ◽

M. Wu ◽

R. Mu ◽

...

Keyword(s):

Electron Microscope ◽

Optical Absorption ◽

Single Crystal ◽

Microstructural Evolution ◽

Nd:Yag Laser ◽

Radiation Effects ◽

New Model ◽

AbstractSynthetic ZrSiO4, HfSiO4, and ThSiO4 single-crystal specimens were irradiated by 800 keV Kr+ ions, and the microstructural evolution was observed in-situ in a transmission electron microscope. All three compounds were found to become amorphous up to temperatures in excess of 600°C. Using a new model, the activation energies for annealing were found to be in the range of 3.1 to 3.6 eV for these compounds. At temperatures above 600°C, the orthosilicates were observed to decompose into the component oxides (e.g., tetragonal ZrO2 + amorphous SiO2 in the case of zircon). A single-crystal zircon specimen was also irradiated with a pulsed picosecond Nd:YAG laser operated at 355 nm, and the resulting microstructure was investigated by optical absorption, SEM, AFM, and TEM techniques.

Effect of Heat Treatment on the Microstructure of Cu-Cr-Zr Alloy

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.727.166 ◽

2017 ◽

Vol 727 ◽

pp. 166-170 ◽

Cited By ~ 3

Author(s):

Li Jun Peng ◽

Hao Feng Xie ◽

Gao Lei Xu ◽

Guo Jie Huang ◽

Zhen Yang

Keyword(s):

Electron Microscope ◽

Volume Fraction ◽

Homogenization Temperature ◽

Eutectic Structure ◽

Optical Microscope ◽

Heat Treatments ◽

Transmission Electron ◽

The Matrix ◽

Zr Alloy

Effect of Heat treatments on microstructure in a Cu-0.71Cr-0.12Zr alloy (in wt.%) have been investigated. The microstructures are analyzed by optical microscope, scanning electron microscope, transmission electron microscope and high-resolution transmission electron microscope after each step of heat treatments. The results show that the as-cast microstructure of Cu-Cr-Zr alloy is Cu matrix, Cr dendrite and eutectic structure which is composed of Cu and Cu5Zr phase with a fine lamellar structure. By increasing the homogenization temperature or prolonging the holding time, the eutectic structure is dissolved into the matrix gradually and the volume fraction of the Cr phases is obviously reduced. The precipitation of Cr phase prevents from Zr-rich phases dissolving in the matrix. And the proper homogenizing process is 900°C×12 h. When the alloy aged at 450°C for 24 h, the crystallography of Cr precipitates and the orientation relationship between Cr precipitates and Cu matrix is bcc structure and KS-OR, respectively. The disk-shaped precipitate is identified as Cu5Zr phase and their habit plane is parallel to {111}Cu plane.

Surface Morphology of Single-Crystal Ceramics

MRS Proceedings ◽

10.1557/proc-82-463 ◽

1986 ◽

Vol 82 ◽

Cited By ~ 5

Author(s):

D.W. Susnitzky ◽

C.B. Carter

Keyword(s):

Electron Microscope ◽

Surface Morphology ◽

Single Crystal ◽

Total Energy ◽

Thin Foil ◽

Crystalline Materials ◽

Step Movement ◽

Thin Foils ◽

ABSTRACTSurfaces of crystalline materials generally facet and form steps and ledges on low-index planes to reduce their total energy. A conventional wedge-shaped transmission electron microscope (TEM) thin foil, prepared slightly misoriented with respect to a low-index plane, provides a suitable geometry for the study of surface ledges, steps and facets. This TEM study characterizes the surface features of annealed thin foils prepared from various oxides with a range of nominally low-index orientations. Observations from single-crystal α-A12O3 and MgAl2O4 (spinel) will be included.The steps and facets typically form along energetically favorable, low-index planes and bound terraces of low-index orientation. The structure of these features are discussed. In addition, surface step movement has been observed and monitored through a series of reannealing experiments on the same foil.

Philosophical Transactions of the Royal Society of London Series A Physical and Engineering Sciences ◽

Lamellae and their organization in melt-crystallized polymers

10.1098/rsta.1994.0079 ◽

1994 ◽

Vol 348 (1686) ◽

pp. 29-43 ◽

Cited By ~ 64

Keyword(s):

Fine Structure ◽

Thermal Properties ◽

Electron Microscope ◽

Molecular Mechanisms ◽

Mechanical And Thermal Properties ◽

Screw Dislocations ◽

Transmission Electron ◽

Gain Material

Significant advances in knowledge of lamellae and their organization in meltcrystallized polymers have stemmed from the ability to examine internal morphologies systematically with the transmission electron microscope. Spherulites form because the first-forming (dominant) lamellae branch repetitively, often at giant screw dislocations, then diverge substantially creating a skeleton to which later-forming lamellae must accommodate. This sequence promotes chain-folding, invites fractional crystallization and modulates chemical, mechanical and thermal properties of spherulites at the inter-dominant spacing. The key feature of lamellar divergence at screw dislocations is present in individual crystals, probably deriving from pressure of uncrystallized molecular cilia; growing lamellae will also distort very substantially to gain material. If necessary, spacefilling is achieved without lamellar and crystallographic continuity by nucleating new growth at large misorientations. Individual melt-grown crystals have been studied both after extraction from a quenched matrix and in situ in thinned specimens. For polyethylene different lamellar profiles have been placed in context while their fine structure provides insights into molecular mechanisms of growth.