Thermally Activated Nature of Basal and Prismatic Slip in Mg and Its Alloys

2021 ◽  
pp. 53-60
Author(s):  
Mohammed A. Shabana ◽  
Jishnu J. Bhattacharyya ◽  
Marek Niewczas ◽  
Sean R. Agnew
Keyword(s):  
Prismatic Slip ◽  
Thermally Activated

Thermally Activated Motion of a Screw Dislocation Overcoming the Peierls Potential for Prismatic Slip in an hcp Lattice

1998 ◽  
Vol 37 (Part 1, No. 7A) ◽  
pp. 4086-4091 ◽  
Author(s):  
Keiichi Edagawa ◽  
Takayoshi Suzuki ◽  
Shin Takeuchi
Keyword(s):  
Screw Dislocation ◽  
Prismatic Slip ◽  
Thermally Activated

scholarly journals A CRITICAL REVIEW OF THE PEIERLS MECHANISM

1967 ◽  
Vol 45 (2) ◽  
pp. 983-1016 ◽  
Author(s):  
Pierre Guyot ◽  
John E. Dorn
Keyword(s):  
Activation Volume ◽  
Prismatic Slip ◽  
Thermally Activated ◽  
Covalently Bonded ◽  
Higher Temperature ◽  
Fe Alloys ◽  
Increasing Temperature ◽  
Peierls Model ◽  
Volume Stress ◽  
Good Agreement

A thorough review is made of the application of the Peierls model to the macroscopic plastic deformation of ionic crystals, metals, alloys, and covalently bonded crystals. The effects of the shape of the Peierls hill, kink–kink energies, and the frequency terms on the stress–temperature and activation volume–stress relationships are extended and discussed. Theory is compared with experimental results, giving special emphasis to recent advances. Single-crystal data for [Formula: see text] {110} thermally activated slip in Ta and Mo at low temperatures agree well with the dictates of the Peierls mechanism. Deformation characteristics of polycrystalline Fe alloys containing either 2 wt.% Mn or 11 at.% Mo agree with expectations based on the Peierls mechanism only at temperatures below about 200 °K. At higher temperatures, the effective stress decreases more slowly and the activation volume increases more rapidly with increasing temperature than can be accounted for by the Peierls mechanism. Over this higher temperature range, however, the experimental data are in good agreement with Escaig's mechanism based on the recombination of dissociated screw dislocations. It is also shown that low-temperature [Formula: see text] {123} slip in AgMg, prismatic slip in Ag plus 33 at.% Al, and in Mg plus 6–12 at.% Li occurs by the Peierls mechanism.

Dislocations in alumina deformed by prismatic slip

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).

Thermally activated flow of β-titanium and β-titanium-hydrogen alloys

2000 ◽  
Vol 80 (12) ◽  
pp. 2813-2825
Author(s):  
O. N. Senkov, J. J. Jonas, F. H. Froes
Keyword(s):  
Thermally Activated

Solvent Dependence of Structural Dynamics and Spin-flip Processes in 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (ortho-3CzBN)

2020 ◽  
Author(s):  
Masaki Saigo ◽  
Kiyoshi Miyata ◽  
Hajime Nakanotani ◽  
Chihaya Adachi ◽  
Ken Onda
Keyword(s):  
Dft Calculations ◽  
Excited States ◽  
Structural Changes ◽  
Photophysical Properties ◽  
Delayed Fluorescence ◽  
Time Resolved ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Solvent Dependence ◽  
Acetonitrile Solutions

We have investigated the solvent-dependence of structural changes along with intersystem crossing of a thermally activated delayed fluorescence (TADF) molecule, 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (o-3CzBN), in toluene, tetrahydrofuran, and acetonitrile solutions using time-resolved infrared (TR-IR) spectroscopy and DFT calculations. We found that the geometries of the S1 and T1 states are very similar in all solvents though the photophysical properties mostly depend on the solvent. In addition, the time-dependent DFT calculations based on these geometries suggested that the thermally activated delayed fluorescence process of o-3CzBN is governed more by the higher-lying excited states than by the structural changes in the excited states.<br>

Mass spectrometric study of allyl radical, allyl bromide and 1,5-hexadiene interactions with oxides; Cobalt suboxide Co3O4

1979 ◽  
Vol 44 (7) ◽  
pp. 2009-2014 ◽  
Author(s):  
Jana Nováková ◽  
Zdeněk Dolejšek
Keyword(s):  
Room Temperature ◽  
Allyl Bromide ◽  
Catalytic Properties ◽  
Mass Spectrometric Study ◽  
Spectrometric Study ◽  
Flow Conditions ◽  
Allyl Radical ◽  
Knudsen Flow ◽  
Thermally Activated ◽  
Radical Interaction

Products of (a) allyl radical interaction with unheated Co3O4, (b) thermally activated 1,5-hexadiene or thermally activated allyl bromide with unheated Co3O4, (c) moderately heated Co3O4 with unheated 1,5-hexadiene or allyl bromide were studied under Knudsen flow conditions. Cobalt suboxide Co3O4, a typical catalyst of deep oxidations yielded acrolein in reaction with allyl radicals as early as at the room temperature of the catalyst. A similar acrolein formation was also observed in the allyl radical interaction with other oxides exhibiting different catalytic properties. It appears that acrolein is in general the primary product of the allyl radical interaction with the oxides. The results are discussed and compared with previous data obtained with MoO3.

Effect of grain size on the vapour phase hydration of monoclinic and triclinic modifications of tricalcium silicate; role of high temperature activation

1991 ◽  
Vol 56 (10) ◽  
pp. 1993-2008
Author(s):  
S. Hanafi ◽  
G. M. S. El-Shafei ◽  
B. Abd El-Hamid
Keyword(s):  
Particle Size ◽  
Vapour Phase ◽  
Tricalcium Silicate ◽  
Active Centers ◽  
Thermally Activated ◽  
Grain Sizes ◽  
Intermediate Size ◽  
Surface Active ◽  
Temperature Activation

The hydration of tricalcium silicate (C3S) with three grain sizes of monoclinic (M) and triclinic (T) modifications and on their thermally activated samples were investigated by exposure to water vapour at 80°C for 60 days. The products were investigated by XRD, TG and N2 adsorption. The smaller the particle size the greater was the hydration for both dried and activated samples from (M). In the activated samples a hydrate with 2θ values of 38.4°, 44.6° and 48.6° could be identified. Hydration increased with particle size for the unactivated (T) samples but after activation the intermediate size exhibited enhanced hydration. Thermal treatment at 950°C of (T) samples increased the surface active centers on the expense of those in the bulk. Changes produced in surface texture upon activation and/or hydration are discussed.

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