The Determination of the Type of Stacking Faults in Face Centered Cubic Alloys by Means of Contrast Effects in the Electron Microscope

The crystalline structure assembled out of charge-stabilized asymmetric dumbbell-like colloidal particles in ethyl alcohol by sedimentation has been probed using small-angle X-ray scattering with microradian resolution. The existence of plastic face-centered cubic crystals was inferred from the observed Bragg peaks. The presence of stacking faults and the mosaic structure of the sample lead to the appearance of diffuse scattering, forming Bragg scattering cylinders in the three-dimensional reciprocal space. The quality of the crystalline structure, as ascertained from a detailed analysis of the diffuse scattering intensity distribution, indicates the presence of only 1.5% of stacking faults between the hexagonal close-packed layers.

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Experimental Determination of Dissolution Kinetics of Zr-Substituted Gd-Ti Pyrochlore Ceramics: Influence of Chemistry on Corrosion Resistance

MRS Proceedings ◽

10.1557/proc-757-ii6.1 ◽

2002 ◽

Vol 757 ◽

Author(s):

Icenhower J.P. ◽

Weber W.J. ◽

Hess N.J. ◽

Thevuthasen S. ◽

Begg B.D. ◽

...

Keyword(s):

Corrosion Resistance ◽

Dissolution Kinetics ◽

Fluorite Structure ◽

Annealed Specimen ◽

Face Centered Cubic ◽

Zirconium Content ◽

The Face ◽

Flow Through ◽

Face Centered

ABSTRACTThe corrosion resistance of a series of zirconium-substituted gadolinium pyrochlore, Gd2(Ti1-x Zrx)2O7, where x = 0.0, 0.25, 0.50, 0.75, and 1.00, were evaluated using single-pass flow-through (SPFT) apparatus at 90°C and pH = 2. The zirconate end-member, Gd2Zr2O7, has a defect fluorite structure, which distinguishes it from the face-centered cubic structure of the true pyrochlore specimens. In addition to the chemical variation, the samples include annealed, un-annealed, and ion-bombarded monoliths. In the case of the titanate end-member, Gd2Ti2O7, the annealed specimen exhibited the least reactivity, followed by the un-annealed and ion-bombarded samples (2.39×10-3, 1.57×10-2, and 1.12×10-1 g m-2 d-1, respectively). With increasing zirconium content, the samples displayed less sensitivity to processing or surface modification with the zirconate end-member exhibiting no difference in reactivity between annealed, un-annealed, and ion-bombarded specimens (rate = 4.0×10-3 g m-2 d-1). In all cases, the dissolution rate decreased with increasing zirconium content to the Gd2(Ti0.25Zr0.75)2O7 composition (1.33x10-4 g m-2 d-1), but the zirconate end-member yielded rates nearly equal to that of the titanate end-member. These results demonstrate that to achieve the greatest radiation and corrosion resistance in this series, the Gd2(Ti0.25Zr0.75)2O7 composition should be considered.

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Stacking Faults in Crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100100998 ◽

1968 ◽

Vol 26 ◽

pp. 250-251

Author(s):

P. C. J. Gallagher

Keyword(s):

Stacking Faults ◽

Elastic Equilibrium ◽

Stacking Fault ◽

Stacking Fault Energy ◽

Major Influence ◽

Face Centered Cubic ◽

Degree Of Dissociation ◽

Partial Dislocations ◽

Layer Structures ◽

Face Centered

Stacking faults are an important substructural feature of many materials, and have been widely studied in layer structures (e.g. talc) and in crystals with hexagonal and face centered cubic structure. Particular emphasis has been placed on the study of faulted defects in f.c.c. alloys, since the width of the band of fault between dissociated partial dislocations has a major influence on mechanical properties.Under conditions of elastic equilibrium the degree of dissociation reflects the balance of the repulsive force between the partials bounding the fault, and the attractive force associated with the need to minimize the energy arising from the misfits in stacking sequence. Examples of two of the faulted defects which can be used to determine this stacking fault energy, Υ, are shown in Fig. 1. Intrinsically faulted extended nodes (as at A) have been widely used to determine Υ, and examples will be shown in several Cu and Ag base alloys of differing stacking fault energy. The defect at B contains both extrinsic and intrinsic faulting, and readily enables determination of both extrinsic and intrinsic fault energies.

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Research on the Microstructure of Solid FeS by TEM

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.217-218.1098 ◽

2011 ◽

Vol 217-218 ◽

pp. 1098-1101

Author(s):

Li Na Zhu ◽

Cheng Biao Wang ◽

Hai Dou Wang ◽

Bin Shi Xu ◽

Jia Jun Liu ◽

...

Keyword(s):

Electron Microscope ◽

Electron Diffraction ◽

Transmission Electron Microscope ◽

Solid Lubricant ◽

Hexagonal Structure ◽

Face Centered Cubic ◽

Transmission Electron ◽

Different Shapes ◽

Cubic Structure ◽

Face Centered

The microstructures of three kinds of synthetical solid FeS, acting as a solid lubricant, which includes FeS bulk, FeS particle and FeS powder, were studied by transmission electron microscope (TEM) in this article. The TEM photographs showed that different shapes of FeS had quite dissimilar characteristics. The texture of FeS powder was the loosest among the three shapes, and it tended to forming flocculent aggregation; while FeS bulk and FeS particle were more dispersive. The electron diffraction results showed that the crystals of solid FeS were composed of many single crystals and multi-crystals, with two kinds of crystalline structure- hexagonal structure and face-centered cubic structure.

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Ultrastrong Al0.1CoCrFeNi high-entropy alloys at small scales: effects of stacking faults vs. nanotwins

Nanoscale ◽

10.1039/c8nr03573c ◽

2018 ◽

Vol 10 (28) ◽

pp. 13329-13334 ◽

Cited By ~ 19

Author(s):

Xiaobin Feng ◽

Jinyu Zhang ◽

Kai Wu ◽

Xiaoqing Liang ◽

Gang Liu ◽

...

Keyword(s):

Stacking Faults ◽

Maximum Strength ◽

High Entropy Alloy ◽

High Entropy Alloys ◽

Face Centered Cubic ◽

High Entropy ◽

Small Scales ◽

Face Centered

The present stacking faulted and nanotwinned Al0.1CoCrFeNi high-entropy alloy pillars achieved the maximum strength among face-centered cubic structured metals.

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The determination of solute atom displacements in mixed dumbbell interstitials for the face-centered-cubic lattice

Canadian Journal of Physics ◽

10.1139/p78-138 ◽

1978 ◽

Vol 56 (8) ◽

pp. 1057-1070 ◽

Cited By ~ 43

Author(s):

N. Matsunami ◽

M. L. Swanson ◽

L. M. Howe

Keyword(s):

Solute Atom ◽

The Body ◽

Continuum Approximation ◽

Face Centered Cubic ◽

Cubic Lattice ◽

The Face ◽

Solute Atoms ◽

Face Centered ◽

Small Solute

Interactions between irradiation-produced defects and solute atoms in metals have been investigated using the channeling technique. The interaction of interest in this investigation is the trapping of self interstitials by small solute atoms thus creating a [Formula: see text] mixed dumbbell, consisting of a host atom and a solute atom straddling a lattice site in the face-centered-cubic lattice. The displacement of solute atoms from lattice sites in the mixed dumbbell configuration was determined by comparing the experimentally observed normalized yields from solute atoms and from host atoms with the yields calculated analytically using the continuum approximation. The solute atoms in Al–Mn, Al–Cu, and Cu–Be mixed dumbbells were situated at 0.5 Å from the body-centered position, whereas the Ag atoms in Al–Ag dumbbells were 0.7 Å from this position. This result is consistent with the theoretical expectation that the smallest solute atoms are displaced the greatest amount in mixed dumbbells. In addition, experimentally obtained solute atom yields for [Formula: see text] and [Formula: see text] angular scans were compared with calculated scans. It was concluded that for large displacements of solute atoms into the flux peaking region, the analytical (continuum) calculation is a reliable method of determining solute atom displacements, either from the aligned yields or from the angular scans.

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