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screw dislocations

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Series: ASM Technical Books
Publisher: ASM International
Published: 01 October 2021
DOI: 10.31399/asm.tb.ciktmse.t56020001
EISBN: 978-1-62708-389-8
..., and how they respond to applied stresses and strains. The chapter makes extensive use of graphics to illustrate crystal lattice structures and related concepts such as vacancies and interstitial sites, ion migration, volume expansion, antisite defects, edge and screw dislocations, slip planes, twinning...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 October 2021
DOI: 10.31399/asm.tb.ciktmse.t56020013
EISBN: 978-1-62708-389-8
... screw dislocations stacking sequence Problem 1: Low-Density Steels Problem 2: Charge Neutrality in Ionic Materials Problem 3: Miscibility in Binary Systems Problem 4: Octahedral Interstitials in <italic>fcc</italic> Crystals Problem 5: Distorted Octahedral Interstitials in a <italic>bcc...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 June 2008
DOI: 10.31399/asm.tb.emea.t52240017
EISBN: 978-1-62708-251-8
... to the displacement vector, u ( b ∥ u ). Fig. 2.7 Burgers circuit and vector for line dislocation. Source: Ref 1 The other important type of line dislocation is the screw dislocation ( Fig. 2.8 ). The term screw dislocation is used because of the spiral surface formed by the atomic planes around...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 October 2021
DOI: 10.31399/asm.tb.ciktmse.9781627083898
EISBN: 978-1-62708-389-8
Series: ASM Technical Books
Publisher: ASM International
Published: 01 January 2015
DOI: 10.31399/asm.tb.spsp2.t54410213
EISBN: 978-1-62708-265-5
... Solutions , Metall. Trans. , Vol 3 , 1972 , p 5 – 26 10.1007/BF02680580 11.13 Vitek V. and Duesbery M.S. , The Behavior of Screw Dislocations in BCC Metals under the Effect of Applied Stresses Other than Pure Shear , Mechanical Properties of BCC Metals , Meshii M. , Ed...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 March 2012
DOI: 10.31399/asm.tb.pdub.t53420363
EISBN: 978-1-62708-310-2
.... A.44 Frank-Read mechanism for dislocation multiplication. Source: Ref A.1 Fig. A.45 Examples of dislocation interactions. Source: Ref A.1 Fig. A.35 Burgers circuit and vector for line dislocation. Source: Ref A.5 as published in Ref A.1 Fig. A.36 Screw...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 January 2015
DOI: 10.31399/asm.tb.spsp2.t54410405
EISBN: 978-1-62708-265-5
... microstructures and for the diffusion of carbon in bcc iron ( Ref 18.12 ). Transmission electron microscopy, Fig. 18.9 , showed that the dislocation structure of the martensite in specimens in which serrated yielding had developed consisted of residual linear arrays of screw dislocation lines, in contrast...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 January 2015
DOI: 10.31399/asm.tb.spsp2.t54410017
EISBN: 978-1-62708-265-5
... associated with dislocations. One is that associated with edge dislocations, as shown in Fig. 3.16 . The other is that of a screw dislocation, which may be considered to be represented as the displacements associated with a spiral staircase around a dislocation line at its center. The Burgers vector...
Series: ASM Technical Books
Publisher: ASM International
Published: 31 December 2020
DOI: 10.31399/asm.tb.phtbp.t59310001
EISBN: 978-1-62708-326-3
... of surface defects occur within crystals and are dependent on the crystalline structure. Surface defects within a crystal lattice can occur by: Most metals have a large number of mixed dislocations, which are any combination of an edge dislocation and a screw dislocation. The numerous dislocations...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 October 2011
DOI: 10.31399/asm.tb.mnm2.t53060013
EISBN: 978-1-62708-261-7
... (high SFE). Some representative SFEs are given in Table 2.3 . Most metals have a large number of mixed dislocations, which are any combination of an edge dislocation and a screw dislocation. The numerous dislocations allow ample opportunity for motion along the slip planes within the crystalline...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 March 2006
DOI: 10.31399/asm.tb.fdsm.t69870375
EISBN: 978-1-62708-344-7
..., and the solid circles represent atoms in the plane just below the slip plane. Source: Ref A.28 Fig. A.15 Screw dislocation. (a) The slip that produces a screw dislocation. Unit slip has occurred over ABCD . The screw dislocation AD is parallel to the slip vector. (b) Arrangement of atoms around...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2018
DOI: 10.31399/asm.tb.fibtca.t52430027
EISBN: 978-1-62708-253-2
... by misalignment of atoms surrounding it. There are two types of dislocations: edge dislocations and screw dislocations. Typical values for the density of dislocations in a metal in an annealed condition are 10 10 to 10 12 per m 2 ( Ref 3.1 ). An edge dislocation causes lattice distortion along the end...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2006
DOI: 10.31399/asm.tb.ex2.t69980141
EISBN: 978-1-62708-342-3
... can move in this plane—there is one more lattice plane than on the other ( Fig. 4.6a ). In a screw dislocation, the lattice areas are displaced relative to each other so that the atoms are arranged around the dislocation line like a spiral ( Fig. 4.6b ). A real, usually randomly curved dislocation...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 July 2009
DOI: 10.31399/asm.tb.bcp.t52230131
EISBN: 978-1-62708-298-3
... transformation from NbBe 12 to Nb 2 Be 17 (the latter structure is very closely related to the former) and could account for enhanced dislocation mobility and the promotion of high-temperature deformation. Atomistic modeling has been performed for the a[100] edge and screw dislocations, and the a/2[100] screw...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 June 1983
DOI: 10.31399/asm.tb.mlt.t62860237
EISBN: 978-1-62708-348-5
... type is the screw dislocation. A screw dislocation would be produced if the atomic plane above the cut in Fig. 7.2a were translated one atomic spacing perpendicular to the plane of the figure. Edge and screw dislocations both produce strain by their motion through the crystal lattice. Figure 7.2...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 January 2015
DOI: 10.31399/asm.tb.spsp2.t54410439
EISBN: 978-1-62708-265-5
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 January 2015
DOI: 10.31399/asm.tb.spsp2.t54410063
EISBN: 978-1-62708-265-5
... at a higher magnification. Relatively straight dislocation lines in two directions are visible. By selected-area diffraction techniques ( Ref 5.42 ), the preferred directions were shown to correspond to 〈111〉 directions and, therefore, the dislocations are mostly screw dislocations. This type of dislocation...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 March 2006
DOI: 10.31399/asm.tb.fdsm.t69870237
EISBN: 978-1-62708-344-7
... role in creating dislocations, breaking up grains into subgrains, and causing microscopic imperfections to coalesce into larger flaws. It also discusses the factors that contribute to the development and propagation of fatigue cracks, including surface deterioration, volumetric and environmental...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2015
DOI: 10.31399/asm.tb.cpi2.t55030148
EISBN: 978-1-62708-282-2
... enhances dislocation motion (generally, screw dislocations) and the creation of dislocations at surfaces and/or crack tips, leading to softening of the material on a localized scale. Although this behavior has been observed in certain steels, hardening by hydrogen has also been found. Careful high...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 April 2013
DOI: 10.31399/asm.tb.imub.t53720117
EISBN: 978-1-62708-305-8
... or the load may be administered via precision cut machine screws driven by the necessary gears, reducers, and motor to provide a suitable travel speed. In some light capacity machines (only a few hundred pounds maximum), the force is applied by an air piston and cylinder. Gear driven systems obtain load...