scholarly journals Study on the Softening Behavior of Cu–Cr–In Alloy during Annealing

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 312 ◽  
Author(s):  
Yunqing Zhu ◽  
Linsheng Tang ◽  
Weibin Xie ◽  
Huiming Chen ◽  
Hang Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Experimental Data ◽  
Activation Energy ◽  
Transmission Electron Microscopy ◽  
Electron Back Scatter Diffraction ◽  
Self Diffusion ◽  
Softening Behavior ◽  
Transmission Electron ◽  
Dislocation Movement ◽  
Microhardness Tester

The softening behavior of a cold-drawn Cu–Cr–In alloy was investigated during annealing between 450 °C and 700 °C. The properties and microstructure evolution of the alloy were characterized using a microhardness tester, electron back-scatter diffraction, and transmission electron microscopy. Elemental In addition was found to hinder the dislocation movement and delay the recovery and recrystallization of the Cu–Cr–In alloy. The experimental data were analyzed using the Johnson–Mehlv–Avramiv–Kolmogorov model. The activation energy of recrystallization of the 60% cold-drawn Cu0.54Cr0.17In alloy was 188.29 ± 18.44 kJ/mol, and the recrystallization mechanism of the alloy was attributed mainly to Cu self-diffusion.

CoSi2 Precipitate Coarsening During Formation of Buried Epitaxial Cosi2 Layers By Ion Beam Synthesis

1990 ◽  
Vol 201 ◽  
Author(s):  
R. Jebasinski ◽  
S. Mantl ◽  
K. Radermacher ◽  
P. Fichtner ◽  
W. Jăger ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Activation Energy ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Microstructural Evolution ◽  
Annealing Temperature ◽  
Ion Beam ◽  
Precipitate Coarsening ◽  
Annealing Temperatures ◽  
Transmission Electron

AbstractThe coarsening of CoSi2 precipitates and the microstructural evolution of (111) Si implanted with 200 keV Co+ ions at 350°C and fluences of 1×1016cm−2 and 6×1016cm−2 were investigated as a function of depth, annealing temperature and annealing time using Rutherford Backscattering Spectroscopy (RBS) and Transmission Electron Microscopy (TEM). After annealing cross-section TEM micrographs show a layered array of platelet-shaped precipitates with preferred facets on {111} planes. The fraction of Co-atoms, that were redistributed during the different annealing temperatures and times, has been used to determine an activation energy for the precipitate coarsening. By applying the Meechan-Brinkman and the change-of-slope methods, we obtained activation energies in the range of 3.2 – 3.6 eV.

Multiple twinning of diamond synthesized by acetylene flame

2004 ◽  
Vol 219 (8) ◽  
Author(s):  
Sam Ick Son ◽  
Su Jin Chung
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Electron Back Scatter Diffraction ◽  
The Other ◽  
Hrtem Image ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Multiple Twinning ◽  
Ebsd Method

AbstractThe relation between the domains and domain boundaries of multiple twins of diamond were investigated by the electron back scatter diffraction (EBSD) method and high resolution transmission electron microscopy (HRTEM). Multiple twinned diamonds have two types of icosahedral morphologies. One is an almost perfect icosahedron in which all of the faces are {111} faces. The other is a hollow icosahedron similar to one of the Kepler-Poinsot polyhedrons. The indented negative trigonal faces are formed from the {100} faces of a cube. It was confirmed that the convex edges of the twinned icosahedron corresponded to the Σ3 boundaries, whereas the concave edges were assigned to the Σ9 twin boundary by means of the EBSD analysis.It was confirmed from the HRTEM image that a series of dislocations compensate for the mismatching angle which occurs after five successive twinning.

Compressive creep of dense Bi2Sr1.7CaCu2Ox

1992 ◽  
Vol 7 (9) ◽  
pp. 2360-2364 ◽  
Author(s):  
J.L. Routbort ◽  
K.C. Goretta ◽  
D.J. Miller ◽  
D.B. Kazelas ◽  
C. Clauss ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Activation Energy ◽  
Transmission Electron Microscopy ◽  
Steady State ◽  
Steady State Creep ◽  
Steady State Creep Rate ◽  
Lower Stress ◽  
Dislocation Glide ◽  
Transmission Electron ◽  
Partial Pressures

Dense polycrystalline Bi2Sr1.7CaCu2Ox (2212) was deformed from 780–835 °C in oxygen partial pressures, Po2, of 103 to 2 × 104 Pa. Results could be divided into two stress regimes: one at lower stress in which the steady-state creep rate, ∊, was proportional to stress, γ, having an activation energy of 990 ± 190 kJ/mole and being independent of PO2, and another at higher stress in which ∊ was proportional to σn, with n ≍ 5–6. Transmission electron microscopy supported the interpretation that in the lower-stress viscous regime, creep was controlled by diffusion, whereas dislocation glide and microcracking were responsible for strain accommodation at higher stresses.

scholarly journals Strengthening Mechanisms and Process Controls for Super Waspaloy

1981 ◽  
Author(s):  
W. H. Couts ◽  
R. R. Biederman
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Cycle Fatigue ◽  
Stress Rupture ◽  
Initial Structure ◽  
Cycle Fatigue ◽  
Strengthening Mechanisms ◽  
Transmission Electron ◽  
Dislocation Movement ◽  
Process Controls

Super Waspaloy is an empirically derived thermomechanically processed version of Waspaloy. Microstructures were evaluated at steps in the hammer forge and heat treat sequence to study how the initial structure is derived. Foils taken from hot tensile, stress rupture, and elevated temperature low cycle fatigue bars were examined by transmission electron microscopy after exposure to temperature and stress. The purpose was to discover the microstructural features resistant to dislocation movement and to seek clues for further improvement of the alloy.

Plastic deformation in icosahedral Al–Pd–Mn alloys

1994 ◽  
Vol 9 (2) ◽  
pp. 343-347 ◽  
Author(s):  
J.E. Shield ◽  
M.J. Kramer ◽  
R.W. McCallum
Keyword(s):  
Electron Microscopy ◽  
Activation Energy ◽  
Transmission Electron Microscopy ◽  
Stress Exponent ◽  
Microstructural Analysis ◽  
High Temperature Creep ◽  
Deformation Characteristics ◽  
Cast Sample ◽  
Dislocation Glide ◽  
Transmission Electron

The deformation characteristics of icosahedral Al70Pd21.5Mn8.5 have been investigated by high temperature creep experiments, and the resultant microstructures have been examined by transmission electron microscopy (TEM). From 730 to 780 °C, microstructural analysis revealed that the deformation is controlled by dislocation glide, with an activation energy of 210 ± 30 kJ/mole and a stress exponent of 1.2 ± 0.2. From 780 to 810 °C, microstructures were characteristic of deformation controlled by dislocation glide and climb. The activation energy and stress exponent were determined to be 1700 ± 80 kJ/mole and 2.9 ± 0.3, respectively. Hardness measurements also reflected an increase in dislocation density, as the hardness of the deformed samples was approximately 10% higher than the as-cast sample.

Kinetic Studies of Nanoscale Crystallization in Electronic Materials

1995 ◽  
Vol 405 ◽  
Author(s):  
C. Hayzelden ◽  
J. L. Batstone
Keyword(s):  
Electron Microscopy ◽  
Activation Energy ◽  
Transmission Electron Microscopy ◽  
Low Temperature ◽  
Electronic Materials ◽  
Kinetic Studies ◽  
Subsequent Growth ◽  
Transmission Electron ◽  
Amorphous Si

AbstractWe report a kinetic analysis of low-temperature NiSi2-mediated crystallization of amorphous Si by in situ transmission electron microscopy. The initiation of crystallization by formation of crystalline Si on buried NiSi2 precipitates is shown to have an activation energy of 2.8±0.7eV. Crystallization of the amorphous Si via migrating precipitates of NiSi2 occurs with an activation energy of 2.0±0.2eV. The significance of these activation energies is discussed in terms of possible atomistic mechanisms of crystalline Si initiation and subsequent growth. Amorphous Si is reported to crystallize at temperatures as low as 450°C.

scholarly journals Exploiting the Acceleration Voltage Dependence of EMCD

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1314
Author(s):  
Stefan Löffler ◽  
Michael Stöger-Pollach ◽  
Andreas Steiger-Thirsfeld ◽  
Walid Hetaba ◽  
Peter Schattschneider
Keyword(s):  
Electron Microscopy ◽  
Experimental Data ◽  
Transmission Electron Microscopy ◽  
Elastic Scattering ◽  
Voltage Dependence ◽  
Atomic Scale ◽  
Electron Wave ◽  
Magnetic Signal ◽  
Transmission Electron ◽  
Acceleration Voltage

Energy-loss magnetic chiral dichroism (EMCD) is a versatile method for measuring magnetism down to the atomic scale in transmission electron microscopy (TEM). As the magnetic signal is encoded in the phase of the electron wave, any process distorting this characteristic phase is detrimental for EMCD. For example, elastic scattering gives rise to a complex thickness dependence of the signal. Since the details of elastic scattering depend on the electron’s energy, EMCD strongly depends on the acceleration voltage. Here, we quantitatively investigate this dependence in detail, using a combination of theory, numerical simulations, and experimental data. Our formulas enable scientists to optimize the acceleration voltage when performing EMCD experiments.

Plastic deformation in an Al–Cu–Fe icosahedral alloy

1993 ◽  
Vol 8 (6) ◽  
pp. 1199-1202 ◽  
Author(s):  
J.E. Shield ◽  
M.J. Kramer ◽  
R.W. McCallum
Keyword(s):  
Electron Microscopy ◽  
Activation Energy ◽  
Transmission Electron Microscopy ◽  
Plastic Deformation ◽  
Steady State ◽  
Quasi Steady State ◽  
High Temperature Creep ◽  
Steady State Regime ◽  
Transmission Electron ◽  
State Regime

Al—Cu—Fe quasicrystalline alloys have been deformed by high-temperature creep between 680 and 740 °C. Deformations greater than 30% were achieved without cracking. Analysis of the data in the quasi-steady state regime reveals power law behavior with a stress exponent of 2.5. The activation energy for deformation was determined to be 640 ± 20 kJ/mole in the temperature region investigated. Transmission electron microscopy revealed lamellar defects which appear similar to twins.

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