Trends in Dislocation Core Structures and Mechanical Behavior in B2 Aluminide

MRS Proceedings ◽

10.1557/proc-364-395 ◽

1994 ◽

Vol 364 ◽

Cited By ~ 4

Author(s):

C. Vailhe ◽

D. Farkas

Keyword(s):

High Temperature ◽

Mechanical Behavior ◽

Deformation Mechanism ◽

Dislocation Core ◽

Peierls Stress ◽

Atomistic Simulations ◽

Dislocation Behavior ◽

B2 Structure

AbstractIn an effort to understand the deformation mechanism in high temperature B2 intermetallics, atomistic simulations were carried out for dislocation cores in a series of compounds exhibiting the B2 structure (FeAl, NiAl, CoAl). A comparison was made on the basis of core structures, dislocation splittings and Peierls stress values. The (110) and (112) γ surfaces were computed for these three compounds. The importance of the APB values and the maximum shear faults for explaining the dislocation behavior is discussed.

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Experimental deformation of a synthetic dunite at high temperature and pressure. I. Mechanical behavior, optical microstructure and deformation mechanism

Tectonophysics ◽

10.1016/0040-1951(84)90263-4 ◽

1984 ◽

Vol 110 (3-4) ◽

pp. 233-262 ◽

Cited By ~ 34

Author(s):

David H. Zeuch ◽

H.W. Green

Keyword(s):

High Temperature ◽

Mechanical Behavior ◽

Deformation Mechanism ◽

High Temperature And Pressure ◽

Optical Microstructure ◽

Experimental Deformation ◽

Temperature And Pressure

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Dynamics of Dissociated Dislocations in SI: A Micro-Meso Simulation Methodology

MRS Proceedings ◽

10.1557/proc-538-69 ◽

1998 ◽

Vol 538 ◽

Cited By ~ 3

Author(s):

W. Cai ◽

V.V. Bulatov ◽

J.F. Justo ◽

S. Yip ◽

A.S. Argon

Keyword(s):

Atomistic Simulation ◽

Kinetic Monte Carlo ◽

Dislocation Core ◽

Dislocation Motion ◽

Peierls Stress ◽

Dislocation Mobility ◽

Simulation Methodology ◽

Structure And Dynamics ◽

Dislocation Behavior ◽

Stress Dependent

AbstractThe theory of dislocation motion in materials with high Peierls stress relates dislocation mobility to the underlying kink mechanisms. While one has been able to describe certain qualitative features of dislocation behavior, important details of the atomic core mechanisms are lacking. We present a hybrid micro-meso approach to modeling the mobility of a single dislocation in Si in which the energetics of defect cores and kink mechanisms are treated by atomistic simulation, while dislocation motion under applied stress and at finite temperature is described through kinetic Monte Carlo. Three important aspects pertaining to treating the details of local structure and dynamics of kinks are incorporated in our approach: (1) Realistic complexity of (multiple) kink mechanisms in the dislocation core. (2) Full Peach-Koehler formalism for treatment of curved dislocation. (3) Detailed investigation of interaction between partials. This simulation methodology is used to calculate micron-scale dislocation mobility, with no adjustable parameters; specifically we obtain temperature and stress dependent velocity results that can be compared with experimental measurements.

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Dislocation Core Structure Evolution During Dislocation Glide in FCC Lattices

MRS Proceedings ◽

10.1557/proc-779-w5.2 ◽

2003 ◽

Vol 779 ◽

Cited By ~ 1

Author(s):

M.A. Soare ◽

R.C. Picu

Keyword(s):

Shear Stress ◽

Elastic Field ◽

Dislocation Core ◽

Peierls Stress ◽

Atomistic Simulations ◽

Structure Evolution ◽

Dislocation Glide ◽

The Core ◽

Fcc Lattice ◽

Dislocation Core Structure

AbstractA dislocation core model is developed in terms of a singular decomposition of the elastic field surrounding the defect in a power series of 1/rn. The decomposition is a Laurent expansion beginning with the term corresponding to the Volterra dislocation and continuing with a series of dipoles and multipoles. The analysis is performed for an edge dislocation in an fcc lattice. The field surrounding the dislocation is derived by means of atomistic simulations. The coefficients of the series expansion are determined from the elastic field using path independent integrals. When loaded by a shear stress smaller than the Peierls stress, the core distorts. The distortion up to the instability (Peierls stress) is monitored based on the variation of these coefficients. The stacking fault separating the two partials is characterized, by using a similar procedure, as a source of elastic field.

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Experimental deformation of a synthetic dunite at high temperature and pressure. I. Mechanical behavior, optical microstructure and deformation mechanism

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts ◽

10.1016/0148-9062(85)92111-4 ◽

1985 ◽

Vol 22 (5) ◽

pp. 143

Keyword(s):

High Temperature ◽

Mechanical Behavior ◽

Deformation Mechanism ◽

High Temperature And Pressure ◽

Optical Microstructure ◽

Experimental Deformation ◽

Temperature And Pressure

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Application of TEM to Deformation, Wear, and Fracture of Ceramics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052377 ◽

1974 ◽

Vol 32 ◽

pp. 472-473

Author(s):

B. J. Hockey

Keyword(s):

Wear Resistance ◽

High Temperature ◽

Mechanical Behavior ◽

Brittle Materials ◽

High Temperature Strength ◽

Wide Range ◽

Corrosive Environments ◽

Further Development

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.

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