Analysis of defect structural evolution in fcc metals irradiated with neutrons under well defined boundary conditions

2004 ◽  
Vol 329-333 ◽  
pp. 81-87 ◽  
Author(s):  
T Yoshiie ◽  
Y Satoh ◽  
Q Xu
Keyword(s):  
Boundary Conditions ◽  
Structural Evolution ◽  
Fcc Metals

Global and Local Structural Evolution during Deformation and Annealing of FCC Metals

2007 ◽  
Vol 550 ◽  
pp. 169-180 ◽  
Author(s):  
Niels Hansen
Keyword(s):  
Lamellar Structure ◽  
Structural Changes ◽  
Large Strain ◽  
Structural Evolution ◽  
Structural Difference ◽  
Rolling Texture ◽  
High Angle ◽  
Fcc Metals ◽  
Microstructural Parameters ◽  
Global And Local

Deformation of metals from medium to high strain significantly affect the deformation structure as well as the recovery and recrystallization behaviour when deformed samples are annealed. This behaviour is illustrated for FCC metals of medium to high stacking fault energy, with emphasis on the behaviour of aluminium and aluminium alloys deformed by cold rolling to large strain. The analysis encompasses hardness testing, EBSD and TEM. The deformation microstructure is a lamellar structure of dislocation boundaries and high angle boundaries where the percentages of the latter increases to about 60-80% at large strain. The macrotexture is a typical rolling texture, which is composed of individual texture components present as micrometre and submicrometre size volumes. In the lamellar structure correlations have been established between microstructural parameters and local orientations showing for example variations in stored energy between the texture components and large variations in the spatial distributions of the high angle lamellar boundaries. Such local variations can affect the structural coarsening during recovery at low temperature leading to significant structural difference on a local scale. The local variations in the deformed structure can also significantly affect the structural changes taking place locally during high temperature annealing thereby affecting the evolution of the structure and texture on a macroscopic scale.

Effects of Uniaxial Strain on the Structures of Vacancy Clusters in FCC Metals

2017 ◽  
Vol 898 ◽  
pp. 1340-1350 ◽  
Author(s):  
Fei Ye ◽  
Hong Bo Xv ◽  
Jin Mei Liu ◽  
Ke Tong
Keyword(s):  
Compressive Strain ◽  
Structural Evolution ◽  
The Body ◽  
Uniaxial Strain ◽  
Dominant Type ◽  
Vacancy Clusters ◽  
Fcc Metals ◽  
Stacking Fault Tetrahedron ◽  
Strain Axis ◽  
Simulation Condition

The effects of [001] uniaxial strain on the stable structures and structural evolution of vacancy clusters in fcc metals, Cu, Ni, Al and Fe, have been studied and compared. Under uniaxial strain, the clusters in all these metals tend to align parallel or perpendicular to the strain axis under tensile or compressive strain. Moreover, both the body cluster and the {001} planar cluster become the dominant types. In addition, the stacking fault tetrahedron cluster becomes another dominant type in Al under compressive strain. The cluster structures in Fe are disordered under strain possibly because the pure fcc Fe is thermodynamically unstable under the current simulation condition.

Lithospheric flexure and volcano basal boundary conditions: keys to the structural evolution of large volcanic edifices on the terrestrial planets

2014 ◽  
Vol 401 (1) ◽  
pp. 219-237 ◽  
Author(s):  
Patrick J. McGovern ◽  
Eric B. Grosfils ◽  
Gerald A. Galgana ◽  
Julia K. Morgan ◽  
M. Elise Rumpf ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Structural Evolution ◽  
Terrestrial Planets ◽  
Lithospheric Flexure

scholarly journals Rolling Texture of Cu–30%Zn Alloy Using Taylor Model Based on Twinning and Coplanar Slip

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1351
Author(s):  
Shih-Chieh Hsiao ◽  
Sin-Ying Lin ◽  
Huang-Jun Chen ◽  
Ping-Yin Hsieh ◽  
Jui-Chao Kuo
Keyword(s):  
Boundary Conditions ◽  
Shear Bands ◽  
Rolling Texture ◽  
Mechanical Twinning ◽  
Taylor Model ◽  
Slip Model ◽  
Fcc Metals ◽  
Model Based ◽  
First Approximation ◽  
Zn Alloy

A modified Taylor model, hereafter referred to as the MTCS(Mechanical-Twinning-withCoplanar-Slip)-model, is proposed in the present work to predict weak texture components in the shear bands of brass-type fcc metals with a twin–matrix lamellar (TML) structure. The MTCS-model considers two boundary conditions (i.e., twinning does not occur in previously twinned areas and coplanar slip occurs in the TML region) to simulate the rolling texture of Cu–30%Zn. In the first approximation, texture simulation using the MTCS-model revealed brass-type textures, including Y {1 1 1}⟨1 1 2⟩ and Z {1 1 1}⟨1 1 0⟩ components, which correspond to the observed experimental textures. Single orientations of C (1 1 2)[1 ¯ 1 ¯ 1] and S’ (1 2 3)[4¯ 1¯ 2] were applied to the MTCS-model to understand the evolution of Y and Z components. For the Y orientation, the C orientation rotates toward T (5 5 2)[1 1 5] by twinning after 30% reduction and then toward Y (1 1 1)[1 1 2] by coplanar slip after over 30% reduction. For the Z orientation, the S’ orientation rotates toward T’ (3 2 1)[2 1 ¯4¯] by twinning after 30% reduction and then toward Z (1 1 1)[1 0 1¯] by coplanar slip after over 30% reduction.

Use of the Magnetostatic Analogue In Electromagnetic Lens Engineering

1970 ◽  
Vol 28 ◽  
pp. 360-361
Author(s):  
John W. Coleman
Keyword(s):  
Boundary Conditions ◽  
High Performance ◽  
Force Fields ◽  
Optical Design ◽  
Direct Conversion ◽  
Design Engineering ◽  
Design Data ◽  
Scalar Potentials ◽  
Geometric Elements ◽  
At Will

In the design engineering of high performance electromagnetic lenses, the direct conversion of electron optical design data into drawings for reliable hardware is oftentimes difficult, especially in terms of how to mount parts to each other, how to tolerance dimensions, and how to specify finishes. An answer to this is in the use of magnetostatic analytics, corresponding to boundary conditions for the optical design. With such models, the magnetostatic force on a test pole along the axis may be examined, and in this way one may obtain priority listings for holding dimensions, relieving stresses, etc..The development of magnetostatic models most easily proceeds from the derivation of scalar potentials of separate geometric elements. These potentials can then be conbined at will because of the superposition characteristic of conservative force fields.

Microstructure and reactivity of small metal particles: The role of Ce additives

1992 ◽  
Vol 50 (1) ◽  
pp. 318-319
Author(s):  
L.D. Schmidt ◽  
K. R. Krause ◽  
J. M. Schwartz ◽  
X. Chu
Keyword(s):  
Atmospheric Pressure ◽  
Noble Metals ◽  
Mixed Oxides ◽  
Catalytic Properties ◽  
Chemical Shifts ◽  
Catalytic Converter ◽  
Structural Evolution ◽  
Single Particles ◽  
Small Metal Particles

The evolution of microstructures of 10- to 100-Å diameter particles of Rh and Pt on SiO2 and Al2O3 following treatment in reducing, oxidizing, and reacting conditions have been characterized by TEM. We are able to transfer particles repeatedly between microscope and a reactor furnace so that the structural evolution of single particles can be examined following treatments in gases at atmospheric pressure. We are especially interested in the role of Ce additives on noble metals such as Pt and Rh. These systems are crucial in the automotive catalytic converter, and rare earths can significantly modify catalytic properties in many reactions. In particular, we are concerned with the oxidation state of Ce and its role in formation of mixed oxides with metals or with the support. For this we employ EELS in TEM, a technique uniquely suited to detect chemical shifts with ∼30Å resolution.

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