Inheritance of the Elastic Field of Martensite Nucleation Center by the Control Wave Process Initiating Deformations of Planes {110}c of Cubic Crystals

Many high-angle grain boundaries in cubic crystals are thought to be either coincidence boundaries (1) or coincidence boundaries to which grain boundary dislocations have been added (1,2). Calculations of the arrangement of atoms inside coincidence boundaries suggest that the coincidence lattice will usually not be continuous across a coincidence boundary (3). There will usually be a rigid displacement of the lattice on one side of the boundary relative to that on the other. This displacement gives rise to a stacking fault in the coincidence lattice.Recently, Pond (4) and Smith (5) have measured the lattice displacement at coincidence boundaries in aluminum. We have developed (6) an alternative to the measuring technique used by them, and have used it to find two of the three components of the displacement at {112} lateral twin boundaries in gold. This paper describes our method and presents a brief account of the results we have obtained.

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Microtwinning Evidence For The Apparent Five-Fold Symmetry in T2(Al6Li3Cu)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100125178 ◽

1987 ◽

Vol 45 ◽

pp. 24-25

Author(s):

Kenneth S. Vecchio ◽

David B. Williams

Keyword(s):

Stable Equilibrium ◽

Equilibrium Phase ◽

Convergent Beam Electron Diffraction ◽

Icosahedral Structure ◽

Cubic Crystals ◽

Icosahedral Phases ◽

Heat Treated ◽

Zero Layer ◽

Convergent Beam ◽

Zr Alloy

Since the discovery in 1984 by Shechtman et al. of crystals which display apparent five-fold symmetry, extensive effort has been given to establishing a theoretical basis for the existence of icosahedral phases (eg.2.). Several other investigations have been centered on explaining these observations based on twinning of cubic crystals (eg.3.). Recently, the existence of a stable, equilibrium phase T2Al6 Li3Cu) possessing an icosahedral structure has been reported in the Al-Li-Cu system(4-6).In the present study an Al-2.6wt.%Li-l.5wt.%Cu-0.lwt.%Zr alloy was heat treated at 300°C for 100hrs. to produce large T2 precipitates. Convergent Beam Electron Diffraction (CBED) patterns were obtained from two-fold, three-fold, and apparent five-fold axes of T2 particles. Figure 1 shows the five-fold symmetric zero layer CBED pattern obtained from T2 particles.

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The study of the elastic deformation of a flexible wheel by a cam wave generator

Studia Universitatis Babeș-Bolyai Engineering ◽

10.24193/subbeng.2020.1.6 ◽

2020 ◽

Vol 65 (1) ◽

pp. 51-58

Author(s):

Sava Ianici

Keyword(s):

Numerical Simulation ◽

Finite Element Method ◽

Finite Element ◽

Elastic Deformation ◽

Theoretical Study ◽

Elastic Field ◽

The Finite Element Method ◽

Elastic Deformations ◽

Wave Generator ◽

Two Stages

The paper presents the results of research on the study of the elastic deformation of a flexible wheel from a double harmonic transmission, under the action of a cam wave generator. Knowing exactly how the flexible wheel is deformed is important in correctly establishing the geometric parameters of the wheels teeth, allowing a better understanding and appreciation of the specific conditions of harmonic gearings in the two stages of the transmission. The veracity of the results of this theoretical study on the calculation of elastic deformations and displacements of points located on the average fiber of the flexible wheel was subsequently verified and confirmed by numerical simulation of the flexible wheel, in the elastic field, using the finite element method from SolidWorks Simulation.

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MISORIENTATION DISTRIBUTION FUNCTION FOR CUBIC CRYSTALS

Industrial laboratory Diagnostics of materials ◽

10.26896/1028-6861-2019-85-5-28-32 ◽

2019 ◽

Vol 85 (5) ◽

pp. 28-32

Author(s):

A. S. Kolyanova ◽

Y. N. Yaltsev

Keyword(s):

Distribution Function ◽

Grain Boundaries ◽

Orientation Distribution ◽

Recrystallization Annealing ◽

Misorientation Distribution ◽

Cubic Crystals ◽

Special Boundaries ◽

Pole Figures ◽

Two Samples ◽

Euler Space

A calculation method for obtaining the misorientation distribution function (MDF) for cubic crystals which can be used to estimate the presence or absence of special boundaries in the materials is presented. The calculation was carried out for two samples of Al-Mg-Si alloy subjected to various mechanical and thermal treatments: the first sample is subjected to rolling; the second sample is subjected to recrystallization annealing. MDF is calculated for each sample; the results are presented in the Euler space and in the angle-axis space. The novelty of the method consists in the possibility of gaining data on the grain boundaries from X-ray texture analysis without using electron microscopy. A calculation involving only mathematical operations on matrices was performed on the basis of the orientation distribution function restored from incomplete pole figures. It is shown that no special boundaries are observed in the deformed sample, whereas in the recrystallized alloy, special boundaries are detected at Ʃ = 23, 13, and 17. The shortcoming of the proposed method can be attributed to the lack of accurate data on grain boundaries, since all possible orientation in the polycrystal should be taken into account in MDF calculation.

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Exact and complete electro-elastic field in a half-space of piezoelectric medium with a charged surface electrode: Revisit

ZAMM ‐ Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik ◽

10.1002/zamm.201200015 ◽

2012 ◽

Vol 92 (10) ◽

pp. 816-823

Author(s):

X.Y. Li

Keyword(s):

Half Space ◽

Elastic Field ◽

Piezoelectric Medium ◽

Charged Surface ◽

Surface Electrode

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Electro-elastic field of a piezoelectric quasicrystal medium containing two cylindrical inclusions

Acta Mechanica ◽

10.1007/s00707-021-02955-0 ◽

2021 ◽

Author(s):

Keqiang Hu ◽

S. A. Meguid ◽

Libin Wang ◽

Hui Jin

Keyword(s):

Elastic Field ◽

Cylindrical Inclusions

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Anomalous shape effect of nanosized helium bubble on the elastic field in irradiated tungsten

Scientific Reports ◽

10.1038/s41598-020-80167-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Xinlong Huang ◽

Chenyangtao Lv ◽

Haijian Chu

Keyword(s):

Normal Stress ◽

Elastic Field ◽

Elastic Response ◽

Shape Effect ◽

Triple Junctions ◽

Equilibrium Pressure ◽

Bubble Pressure ◽

Mechanism Transition ◽

Geometry Characteristic ◽

Anomalous Shape

AbstractBubble pressure and elastic response in helium-irradiated tungsten are systematically investigated in this study. An anomalous shape effect is found that the radial normal stress and mean stress distributions around a nanosized void or bubble are far from the spherical symmetry, which is ascribed to polyhedral geometry characteristic of the nanosized bubble and physical mechanism transition from crystal surfaces dominated to the surface ledges and triple junctions dominated. Molecular simulation shows that Young–Laplace equation is not suitable for directly predicting equilibrium pressure for nanosized bubble in crystals. Consequently, a new criterion of average radial normal stress of spherical shell is proposed to polish the concept of equilibrium pressure of helium bubbles. Moreover, the dependences of bubble size, temperature and helium/vacancy ratio (He/Vac ratio) on the bubble pressure are all documented, which may provide an insight into the understanding of mechanical properties of helium-irradiated tungsten.

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