Twining and Slip Activity in Magnesium Single Crystal

AbstractUniaxial μ-compression tests have been performed on single crystal Mg with a <11-20> compression direction, an orientation unfavorable for basal slip. Results show that the early stages of deformation proceed via both twinning and dislocation plasticity. Twinning leads to a reorientation of the crystal favorable for basal slip, typically with the <2-1-1-3> aligned with the compression direction. At a critical strain a large strain burst occurs, and is associated with both rapid propagation of the twin and the activation of basal slip within the twin. Such a mechanistic picture of the deformation behavior is revealed through SEM, EBSD and TEM characterization of the deformation structures.

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Microstructure-Dependent Deform Behavior of a Polycrystalline Ni-Based Superalloy Based on Micropillar Compression

Materials Science Forum ◽

10.4028/www.scientific.net/msf.944.25 ◽

2019 ◽

Vol 944 ◽

pp. 25-32

Author(s):

Gao Feng Tian ◽

Yang Chen ◽

Bin Gan ◽

Yan Yang ◽

Jin Wen Zou

Keyword(s):

Plastic Deformation ◽

Deformation Behavior ◽

Marked Effect ◽

Stacking Faults ◽

Compression Tests ◽

Strain Burst ◽

Dislocation Plasticity ◽

Slip Planes ◽

Micropillar Compression ◽

Critical Resolved Shear Stress

A study was carried out to determine the deform behavior in a polycrystalline Ni-based superalloy based on micropillar compression tests. Three different heat treatments of this alloy were evaluated by systematically controlling the cooling rate from the supersolvus solutioning step, in order to examine the effect of γ' microstructure on the CRSS (Critical Resolved Shear Stress). It is shown that the γ' precipitates have the marked effect on the deform behavior of micropillar, as the size of the secondary γ' in the general microstructure decreased, the CRSS were increased; SEM and TEM examination show that compressive deformation behavior of [110] oriented micropillars is dominated by dislocation plasticity. Cross slip is occurring in different slip planes, and exhibits away slip lines as well as stacking faults across γ/γ' microstructure. The γ' and carbides in this alloy effectively impeded the motion of dislocations and inhibit the strain burst behavior, caused by the running out of dislocations to the surface of micropillars,which leads to the sustained strain hardening the plastic deformation stage of micropillars.

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Electron Microscopy of Shock Loaded Polycrystalline Beryllium

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052547 ◽

1974 ◽

Vol 32 ◽

pp. 506-507 ◽

Cited By ~ 1

Author(s):

J. M. Galbraith ◽

L. E. Murr ◽

A. L. Stevens

Keyword(s):

Electron Microscopy ◽

Wave Propagation ◽

Structural Change ◽

Single Crystal ◽

Diffraction Pattern ◽

Shock Loading ◽

Slip Systems ◽

Compression Tests ◽

X Ray Diffraction ◽

X Ray

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.

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Dislocations in alumina deformed by prismatic slip

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100110179 ◽

1978 ◽

Vol 36 (1) ◽

pp. 606-607

Author(s):

J. Cadoz ◽

J. Castaing ◽

J. Philibert

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Basal Slip ◽

Prismatic Slip ◽

Compression Tests ◽

Thin Sections ◽

Burgers Vector ◽

Maximum Deformation ◽

Transmission Electron ◽

Mechanical Thinning

Plastic deformation of alumina has been much studied; basal slip occurs and dislocation structures have been investigated by transmission electron microscopy (T.E.M.) (1). Non basal slip has been observed (2); the prismatic glide system <1010> {1210} has been obtained by compression tests between 1400°C and 1800°C (3). Dislocations with <0110> burgers vector were identified using a 100 kV microscope(4).We describe the dislocation structures after prismatic slip, using high voltage T.E.M. which gives much information.Compression tests were performed at constant strainrate (∿10-4s-1); the maximum deformation reached was 0.03. Thin sections were cut from specimens deformed at 1450°C, either parallel to the glide plane or perpendicular to the glide direction. After mechanical thinning, foils were produced by ion bombardment. Details on experimental techniques can be obtained through reference (3).

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Spectral Investigation on the Growth and Characterization of NLO Crystals of Thiourea Succinic Acid Single Crystal.

International Journal of Science Technology and Humanities ◽

10.26524/ijsth58 ◽

2015 ◽

Vol 2 (2) ◽

pp. 70-73

Author(s):

Kannan.P ◽

Thambidurai.S ◽

Suresh.N

Keyword(s):

Single Crystal ◽

Succinic Acid ◽

Slow Evaporation Technique ◽

Absorption Studies ◽

Dta Analysis ◽

Evaporation Technique ◽

Ft Ir ◽

Ir Spectroscopic ◽

Thermal Stability Of

Growth of optically transparent single crystals of thiourea succinic acid (TUSA) was grown successfully from aqueous solution by slow evaporation technique. The crystal structure was elucidated using the single crystal XRD. The various functional groups and the modes of vibrations were identified by FT-IR spectroscopic analysis. The optical absorption studies indicate that the optical transparency window is quite wide making its suitable for NLO applications. Thermal stability of the crown crystal carried out by TGA-DTA analysis.

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Design, Analysis, and Characterization of Single Crystal Energy Harvesters for Rotorcraft Wireless Sensor Applications

Journal of the American Helicopter Society ◽

10.4050/jahs.60.022006 ◽

2015 ◽

Vol 60 (2) ◽

pp. 1-10

Author(s):

Michael V. Wozniak ◽

Stephen C. Conlon ◽

Edward C. Smith ◽

Karl M. Reichard

Keyword(s):

Single Crystal ◽

Design Analysis ◽

Wireless Sensor ◽

Energy Harvesters ◽

Sensor Applications

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Heteroleptic [Cu(P^P)(N^N)][PF6] Complexes: Effects of Isomer Switching from 2,2′-biquinoline to 1,1′-biisoquinoline

Crystals ◽

10.3390/cryst11020185 ◽

2021 ◽

Vol 11 (2) ◽

pp. 185

Author(s):

Nina Arnosti ◽

Marco Meyer ◽

Alessandro Prescimone ◽

Edwin C. Constable ◽

Catherine E. Housecroft

Keyword(s):

Crystal Structure ◽

Single Crystal ◽

Nmr Spectra ◽

Phenyl Ether ◽

Quantum Yields ◽

Dynamic Processes ◽

Electrochemical Behaviors ◽

Ambient Temperatures ◽

Π Stacking

The preparation and characterization of [Cu(POP)(biq)][PF6] and [Cu(xantphos)(biq)][PF6] are reported (biq = 1,1′-biisoquinoline, POP = bis(2-(diphenylphosphanyl)phenyl)ether, and xantphos = (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane). The single crystal structure of [Cu(POP)(biq)][PF6] 0.5Et2O was determined and compared to that in three salts of [Cu(POP)(bq)]+ in which bq = 2,2′-biquinoline. The P–C–P angle is 114.456(19)o in [Cu(POP)(biq)]+ compared to a range of 118.29(3)–119.60(3)o [Cu(POP)(bq)]+. There is a change from an intra-POP PPh2-phenyl/(C6H4)2O-arene π-stacking in [Cu(POP)(biq)]+ to a π-stacking contact between the POP and bq ligands in [Cu(POP)(bq)]+. In solution and at ambient temperatures, the [Cu(POP)(biq)][PF6]+ and [Cu(xantphos)(biq)]+ cations undergo several concurrent dynamic processes, as evidenced in their multinuclear NMR spectra. The photophysical and electrochemical behaviors of the heteroleptic copper (I) complexes were investigated, and the effects of changing from bq to biq are described. Short Cu···O distances within the [Cu(POP)(biq)]+ and [Cu(xantphos)(biq)]+ cations may contribute to their very low photoluminescent quantum yields.

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