Download or read book Dislocation Multiplication in the Early Stage of Deformation in Mo Single Crystals written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Initial dislocation structure in annealed high-purity Mo single crystals and deformation substructure in a crystal subjected to 1% compression have been examined and studied using transmission electron microscopy (TEM) techniques in order to investigate dislocation multiplication mechanisms in the early stage of plastic deformation. The initial dislocation density is in a range of 106 (almost equal to) 107 cm−2, and the dislocation structure is found to contain many grown-in superjogs along dislocation lines. The dislocation density increases to a range of 108 (almost equal to) 109 cm−2, and the average jog height is also found to increase after compressing for a total strain of 1%. It is proposed that the preexisting jogged screw dislocations can act as (multiple) dislocation multiplication sources when deformed under quasi-static conditions. The jog height can increase by stress-induced jog coalescence, which takes place via the lateral migration (drift) of superjogs driven by unbalanced line-tension partials acting on link segments of unequal lengths. The coalescence of superjogs results in an increase of both link length and jog height. Applied shear stress begins to push each link segment to precede dislocation multiplication when link length and jog height are greater than critical lengths. This ''dynamic'' dislocation multiplication source is suggested to be crucial for the dislocation multiplication in the early stage of plastic deformation in Mo.

Download or read book Initial Dislocation Structure and Dynamic Dislocation Multiplication in Mo Single Crystals written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Initial dislocation structure in annealed high-purity Mo single crystals and deformation substructure in a crystal subjected to 1% compression have been examined and studied in order to investigate dislocation multiplication mechanisms in the early stages of plastic deformation. The initial dislocation density is in a range of 106 (almost equal to) 107 cm−2, and the dislocation structure is found to contain many grown-in superjogs along dislocation lines. The dislocation density increases to a range of 108 (almost equal to) 109 cm−2, and the average jog height is also found to increase after compressing for a total strain of 1%. It is proposed that the preexisting jogged screw dislocations can act as (multiple) dislocation multiplication sources when deformed under quasi-static conditions. Both the jog height and length of link segment (between jogs) can increase by stress-induced jog coalescence, which takes place via the lateral migration (drift) of superjogs driven by unbalanced line-tension partials acting on link segments of unequal lengths. Applied shear stress begins to push each link segment to precede dislocation multiplication when link length and jog height are greater than critical lengths. This dynamic dislocation multiplication source is subsequently verified by direct simulations of dislocation dynamics under stress to be crucial in the early stages of plastic deformation in Mo single crystals.

Download or read book Direct Observation of Dislocations and Plasticity in Mineral Crystals with Special Reference to Plagioclase written by Karl Earl Seifert and published by . This book was released on 1965 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Crystal Dislocations Their Impact on Physical Properties of Crystals written by Peter Lagerlof and published by MDPI. This book was released on 2019-01-09 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Crystal Dislocations: Their Impact on Physical Properties of Crystals" that was published in Crystals

Download or read book Dislocations and Plastic Behavior of Iron Single Crystals written by Paul J. Fopiano and published by . This book was released on 1961 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dislocation Arrangements in Silver Single Crystals During Stage I Deformation written by Frank J. Worzala and published by . This book was released on 1964 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiscale Phenomena in Materials Experiments in Modeling Volume 578 written by I. M. Robertson and published by Mrs Proceedings. This book was released on 2000-07-20 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: The MRS Symposium Proceeding series is an internationally recognised reference suitable for researchers and practitioners.

Download or read book Elastic plastic Deformation of Molybdenum Single Crystals Shocked to 12 5 GPa written by Anirban Mandal and published by . This book was released on 2016 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: The observed orientation dependence of the elastic wave amplitudes was understood by examining the corresponding resolved shear stresses (tau) on {110} and {112} slip systems determined from quasi-static studies. A comparison of the resolved shear stresses (tau el) on the operative slip planes at the elastic limit and the reported Peierls stress (tauP) for screw dislocations in Mo suggested that elastic wave amplitudes attenuate rapidly for tau > tau P, but no measurable attenuation occurs after tau ~ tau P. Resolved shear stresses corresponding to elastic limits under shock loading were ~10--50 times larger than the shear stresses under quasi-static loading, a likely consequence of the large Peierls stress in Mo crystals.

Download or read book Dislocation Multiplication in Shock deformed Copper Single Crystals written by Michael Ross Keegan and published by . This book was released on 1967 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Single Crystal Deformation Experiments for Validation of Dislocation Dynamics Simulations written by and published by . This book was released on 2003 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new experimental apparatus has been developed for performing compression deformation experiments on high-purity Mo single crystals. These experiments provide data that can validate 3-D dislocation dynamics (DD) simulations. The experiments are performed under conditions that allow unconstrained deformation; thus, a relatively uniform state of axial stress is maintained during deformation. In the following sections, we describe the new experimental apparatus and our results from experiments performed at ambient temperature at a strain rate of s−1. Validation criteria based on the Mo experiments may include comparing the stress-strain response using 3-D strain information, the predicted slip-system yield, and work-hardening behavior.

Download or read book Advances in Computational Engineering Sciences 2000 written by and published by . This book was released on 2000 with total page 968 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Introduction to Dislocations written by Derek Hull and published by . This book was released on 1965 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Deformation and Dislocation Dynamics in Silicon Single Crystals written by Thomas Alan Taylor and published by . This book was released on 1968 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dislocations in Solids written by Hiroshi Suzuki and published by CRC Press. This book was released on 2023-03-08 with total page 691 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume comprises the Proceedings of the Yamada Conference IX on Dislocations in Solids, held in August 1984 in Tokyo. The purpose of the conference was two-fold: firstly to evaluate the increasing data on basic properties of dislocations and their interaction with other types of defects in solids and, secondly, to increase understanding of the material properties brought about by dislocation-related phenomena. Metals and alloys, semi-conductors and ions crystals were discussed. One of the important points of contention was the electronic state at the core of dislocation. Another was the dislocation model of amorphous structure.

Download or read book Dislocation Dynamics During Plastic Deformation written by Ulrich Messerschmidt and published by Springer Science & Business Media. This book was released on 2010-04-19 with total page 509 pages. Available in PDF, EPUB and Kindle. Book excerpt: Along with numerous illustrative examples, this text provides an overview of the dynamic behavior of dislocations and its relation to plastic deformation. It introduces the general properties of dislocations and treats the dislocation dynamics in some detail.

Download or read book Patterns Defects and Materials Instabilities written by D. Walgraef and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the origin of spatio-temporal order in open systems far from thermal equilibrium and the selection mechanisms of spatial struc tures and their symmetries is a major theme of present day research into the structures of continuous matter. The development of methods for pro ducing spatially ordered microstructures in solids by non-equilibrium methods opens the door to many technological applications. It is also be lieved that the key to laminar/turbulence transitions in fluids lies in the achievement of spatio-temporal order. Let us also emphasize the fact that the idea of self-organization in it self is at the origin of a reconceptualisation of science. Indeed, the appear ance of order which usually has been associated with equilibrium phase transitions appears to be characteristic of systems far from thermal equi librium. This phenomenon which was considered exceptional at first now the rule in driven systems. The chemical oscillations obtained appears to be in the Belousov-Zhabotinskii reaction were initially considered to be ther modynamically impossible and were rejected by a large number of chemists. Now these oscillations and related phenomena (waves, chaos, etc. ) are the subject of intensive research and new classes of chemical oscil lators have been recently discovered. Even living organisms have long been considered as the result of chance rather than necessity. Such points of view are now abandoned under the overwhelming influence of spatio-tem poral organization phenomena in various domains ranging from physics to biology via chemistry, nonlinear optics, and materials science .

Download or read book Dislocations written by Jacques Friedel and published by . This book was released on 1967 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt: