Last edited by Tagal
Friday, December 4, 2020 | History

2 edition of Dynamic strain ageing and jerky flow in Al - Mg single crystals. found in the catalog.

Dynamic strain ageing and jerky flow in Al - Mg single crystals.

S. MacEwen

Dynamic strain ageing and jerky flow in Al - Mg single crystals.

  • 242 Want to read
  • 34 Currently reading

Published in [Toronto] .
Written in English

    Subjects:
  • Deformations (Mechanics),
  • Dislocations in crystals,
  • Plasticity

  • Edition Notes

    ContributionsToronto, Ont. University.
    The Physical Object
    Pagination148 leaves.
    Number of Pages148
    ID Numbers
    Open LibraryOL18880240M

    TABLEOFCONTENTS Page ACKNOWLEDGEMENTS iii LISTOFTABLES vi LISTOFFIGURES vii ABSTRACT xii CHAPTER I INTRODUCTION 1 II PRINCIPLEOFSTRAINAGING 5 Introduction 5 MechanismsofStrainAging, 8 TheoriesofDynamicStrainAging 11 TheCottrel1 Theory 11 TheMcCormickTheory 14 ThevandenBeukelTheory 16 TheReed-HillTheory 19 III . @article{osti_, title = {Analysis on the amplitude of serrated flow associated with the Portevin-LeChatelier effect of substitutional fcc alloys}, author = {Chen, M C and Chen, L H and Lui, T S}, abstractNote = {The serration of flow curve is a common feature of the Portevin-LeChatelier effect of substitutional fcc alloys. Under the condition that the onset strain of serration decreases. Abstract: In this work, Al-Mg-Mn-Si alloy () in the as-received and severe plastically deformed states was used. Plastic deformation was carried out by hydrostatic extrusion, and three different true strain values were applied , and All specimens were . @article{osti_, title = {High strain rate deformation in FCC metals and alloys}, author = {Follansbee, P S}, abstractNote = {The effect of strain rate, and particularly of high strain rates, on deformation mechanisms in materials is of fundamental interest to those who model and analyze dynamic loading. In many materials the strain rate sensitivity is known to increase dramatically when.


Share this book
You might also like
The Jews of South Africa

The Jews of South Africa

Melton Mowbray

Melton Mowbray

Family and health

Family and health

Islam and modernity in Turkey

Islam and modernity in Turkey

Consolidated Fund Act 1997

Consolidated Fund Act 1997

Type F.M.packaged water-tube boilers.

Type F.M.packaged water-tube boilers.

Protection of Alaskan Fisheries

Protection of Alaskan Fisheries

I knew Sarah Bernhardt

I knew Sarah Bernhardt

Assessment of the Influence of Gas Supersaturation on Salmonids in the Nechako River in Relation to Kemano Completion.

Assessment of the Influence of Gas Supersaturation on Salmonids in the Nechako River in Relation to Kemano Completion.

The four green fields

The four green fields

From pocket borough to parliamentary democracy

From pocket borough to parliamentary democracy

Rivers of blood, years of darkness.

Rivers of blood, years of darkness.

Du realisme au surrealisme

Du realisme au surrealisme

Dynamic strain ageing and jerky flow in Al - Mg single crystals. by S. MacEwen Download PDF EPUB FB2

Title: Dynamic strain ageing and jerky flow in Al-Mg single crystals: Authors: MacEwen, S. R.; Ramaswami, B. Publication: Philosophical Magazine, vol. 22, issue For example, Brindley and Worthington [22] found that jerky flow occurred at higher temperatures in single crystals of Al-3% Mg than in polycrystals despite the fact that the high temperature drop in the Dynamic strain ageing and jerky flow in Al - Mg single crystals.

book stress occurred at the same temperature in the polycrystals as in the single crystals, indicating that the same dis- location mechanisms were operative in both types of by: Dynamic strain aging characteristics have been observed in MgO single crystals when deformed above °C.

Serrated flow has been identified, which has been shown to depend on the deformation rate and by: 9. The model of dynamic strain aging as suggested by Hong [7–9 ], was used to describe the stress dependence of the steady state creep rate in Al-Mg solid solution alloys [ 1, 2 ]; the stress exponent for creep in those alloys exhibits a minimum value of about 3 at intermediate stresses.

Strain effects are inherent in the mechanisms of dynamic and static strain ageing, Figure lo shows the strain dependence of the SRS in impure titanium (which is further referred to as Ti-O), after.

Dynamic strain aging (DSA) is ubiquitous in metal alloys, including Al, Cu, Fe, and Ni-base alloys, when they are plastically deformed within specific ranges of temperature and strain Cited by: A constitutive model proposed by McCormick [() Theory of flow localization due to dynamic strain ageing.

Acta. Metall, –] based on dislocation-solute interaction and describing. An experimental investigation into the dynamic strain ageing (DSA) of a wrought Ni-base superalloy Li was conducted.

Characteristics of jerky flow have been studied at intermediate temperatures. Incorporation of Dynamic Strain Aging Into a Viscoplastic Self-Consistent Model for Predicting the Negative Strain Rate Sensitivity of Hadfield Steel Acoustic Emission Inspection of Portevin-Le Chatelier Effect and Deformation Mechanisms of Two Mg-Li-Al Alloys The Effect of Nitrogen and Aluminum on the Deformation Behavior of Hadfield Cited by: Dynamic strain aging in Haynes superalloy Magnus Hornqvist¨ 1,2 a, Ceena Joseph3, Christer Persson3, Jonathan Weidow2, and Haiping Lai2 1 GKN Aerospace Engine Systems, R&T Centre, Trollhattan, Sweden¨ 2 Chalmers University of Technology, Department of Applied Physics, Goteborg, Sweden¨Cited by: 4.

experiments are suggested. The physical basis of dynamic strain-aging is, in all views, an increase in the effective dislocation glide resistance due to the mobility of solute atoms above a certain temperature.

In the oldest quantitative model [4], the mobile solutes were assumed to inter- act with the quasi-viscously moving dislocations. Later models recognized that dislocation motion in. Constant strain rate compression tests were performed on Mg-2Zn-2Nd samples over the temperature range 25 to °C and strain rate range to /s.

The deformation conditions under which dynamic strain aging (DSA) takes place were : Tong Wang, Stephen Yue, John J. Jonas. Abstract. Dynamic strain ageing has been observed on straining a Mg–Y–Zn–Gd alloy in both the quenched and the annealed states, where long-period-structural-order phase and solution or Cited by: 1.

Dynamic strain ageing and jerky flow in Al-Mg single crystals. Macewen & B. Ramaswami. Analysis of the flow stress for low-temperature deformation.

Gibbs. Pages: Published online: 20 Aug book review. Reviews of books. Brown. Dynamic strain aging (DSA) and rapid work hardening are typical behaviors observed in medium-Mn transformation-induced plasticity (TRIP) steel.

Three alloys with manganese ranging from to wt pct with calculated room temperature stacking fault energies varying from − to mJ/m2 were investigated. Significant serrations were observed in the stress-strain behavior for two of Cited by: An AA alloy (Al–54Zn–12Mg) was tested for evidence of dynamic strain aging in naturally aged and peak aged condition and under varying conditions in terms of strain rate and temperature.

Materials Science and Engineering, All 7 () 75 Dynamic Strain Aging in Czochralski-grown Silicon Single Crystals T. GROSS, V. MATHEWS, R. DE ANGELIS and K. OKAZAKI Department of Materials Science and Engineering, University of Kentucky, Lexington, K Y (U.S.A.) (Received ; in revised form Janu ) Abstract Constant extension rate Cited by:   A phenomenological jerky flow model was developed in which macroscale plastic strain rates are defined by dislocation kinetics.

The model takes into account destructive processes governed by shear and bulk defect accumulation. At the heart of the model lie equations of solid mechanics and relaxation-type constitutive equations. A loaded elastoplastic solid is treated as a nonlinear dynamic Cited by: 9. The effect of pre-ageing (PA) on dynamic strain ageing (DSA) in Al-Mg-Si alloys with different Mg/Si ratios has been studied by using hardness measurements, tensile testing, three dimensional atom.

Then, it is at that level that dynamic strain ageing is defined, and where discontinuous flow can lead to localization and : Yue Zhao, Yue Zhao, Lucile Dezerald, Marta Pozuelo, Xinran Zhou, Jaime Marian.

turn€promotes€strain€localization,€affecting€the€mechanical€performance€of€the€material. Keywords€€€€Dynamic€strain€aging,€austenitic€stainless€steel,€Ni­base€alloy,€mechanical€spectroscopy,€TEM ISBN€(printed) ­­60­­7 ISSN€(printed) ­Cited by: Dynamic strain aging is an instability in plastic flow of materials, associated with interaction between moving dislocations and diffusing solutes.

Although sometimes dynamic strain aging is used interchangeably with the Portevin–Le Chatelier effect, dynamic strain aging refers specifically to the microscopic mechanism that induces the Portevin–Le Chatelier effect. This strengthening mechanism. Fe–43at%Al single crystals were deformed in compression between room temperature and 8C.

The strain rate sensitivity of the flow stress was measured by stress relaxation tests. The dislocation structure of the deformed samples was studied in a high-voltage transmission electron microscope. In the present paper, in order to better understand the third type “dynamic strain aging” occurring during the plastic flow of metals, the uniaxial compressive experimental data ever obtained in University of California, San Diego using an Instron servo-hydraulic testing machine and the Hopkinson technique are systematically by: Dislocation Dragging Mechanisms and Long-Term Strength of Metal Crystals effect is attributed to dynamic strain aging (DSA), in which the isolated solute atoms interact with mobile dislocations during straining.

However, from the dynamically unstable region with the jerky flow. LOCALIZED FLOW (SHEAR BANDS) IN Al AND Al-3%Mg ALLOY Y. Nakayama and K. Modi College of Engineering, University of Osaka Prefecture, SakaiJapan ABSTRACT IT IS WELL known that if a sheet material such as used in sheet forming processes is deformed by tension, following behavior will be observed: the load increases with increasing elongation, diffuse necking (geometrical instability Author: Y.

Nakayama, K. Morii. Abstract. Serrated flow has recently been observed in the ternary Mg-9 wt.% Al-1 wt.% Zn alloy AZ91 at room temperature. Binary and ternary alloys with various contents of Zn and Al have, therefore, been tested to determine the extent to which the individual solutes, Al or Zn, are responsible for the : C.

Corby, C. Caceres and P. Lukac. Sarkar et al. Published online: 13 Article Effect of Al addition on microstructure and mechanical properties of as-cast Mg-4Y-3Nd alloy Wang et al. Published online: 24 Oct Article On the tensile flow stress response of HCu stainless steel employing a dislocation density based model and electron backscatter diffraction measurements.

The U.S. Department of Energy’s Office of Basic Energy Sciences recently established the Center for Excellence in the Synthesis and Processing of Advanced Materials.

Projects at the center typically include several national laboratories, industrial partners, and universities; metal forming is one of eight projects within the center. This article describes the center’s metal forming project Cited by: EFFECT OF STRAIN AGEING IN WELDED AND NON Welded And Non Welded Low Carbon Steel” by ABHISHEK BANERJEE and SUMIT progresses, then it is called dynamic strain-ageing.

Fig- Stress-Strain Curves for low carbon steels showing strain ageing As shown in the above Fig, A is upper yield point, B is lower yield point, BC is the Luders. solute atoms are of the same order of magnitude.

Dynamic Strain Ageing (DSA) is well documented in many dilute alloys such as, e.g.: Al-Mg around room temperature (Kubin et al., ), Fe-C around °C (De, ), or austenitic alloys around °C (Samuel et al., ).

ItsCited by:   Size effects on plasticity in high-entropy alloys - Volume 33 Issue 19 - Indranil Basu, Václav Ocelík, Jeff Th. De HossonCited by: AFM Observation of Fe-Al Single Crystals under in situ Deformation, Acta Physica Polonica a () [92] J.

Vesely, M. Cieslar, M. Slamova. ALCHEMI study of chromium doped iron-aluminides, International Journal of Materials Research () The uniaxial tensile tests were conducted at different temperatures to explore the coupled influence of stacking fault energy (SFE) and short-range clustering (SRC) on the plastic deformation behavior of Cu-Ni alloys.

The results demonstrate that the ultimate tensile strength and uniform elongation decrease with increasing temperature due to the competitive influence of SFE and : Ying Wang, Dong Han, Xiao Wu Li.

Strain localization in ductile single crystals For example, ELAM () and later KARNOPP and SACH~ () found that age-hardened alloys of aluminum displayed pronounced shear instabilities following uniform deformation. BEEVER.V and HONEYCOMBE (), followed by PRICE and.

Temporal and spatial characteristics of serrated plastic flow or the so-called Portevin-Le Chatelier (PLC) deformation bands in a commercial Al % Mg sheet metal due to dynamic strain aging effects were investigated experimentally under quasi-static uniaxial tension.

It was found that the thickness and width of test coupons, applied loading conditions (machine stiffness and crosshead Cited by: Fifty years ago, the study of crystalline plasticity was focused on the strain range covered by tensile tests, i.e., on true strains less than unity; the canonic stress–strain behavior was the succession of stages I, II, and III, the latter supposedly leading to a steady state defining a temperature and strain rate-dependent flow stress limit.

M.L. Weaver and M.J. Kaufman, "An Investigation of Al2Ta and Related Phases in the Ternary Al-Ti-Ta System," Scripta Metallurgica et Materialia, v, pages ().

M.L. Weaver, M.J. Kaufman and R.D. Noebe, "The Effects of Alloy Purity on the Mechanical Behavior of Soft Oriented NiAl Single Crystals," Scripta Metallurgica et Materialia, v, pages ().

@article{osti_, title = {Serrated yielding in Al-Li alloys}, author = {Kumar, S and McShane, H B}, abstractNote = {Serrated yielding (SY) during tensile testing has been observed in Al-Li alloys, both in the binary and the commercial quaternary alloys, in single crystal as well as polycrystalline materials.

Serrated yielding is commonly explained by a dynamic strain aging (DSA) model. The microscopic origin of the PLC effect is associated to the dynamic strain aging (DSA) phenomenon resulting from the interaction between mobile dislocations and the clouds of impurities. The solute atoms diffuse towards dislocations during their temporary arrests at local obstacles and increases, consequently, the plastic flow stress.

When the slip step is large and strain rate is high as in the case of dynamic strain aging, we have observed a spike of AE activity.

The origin of continuous emissions The hot air stress strain aging results for hours at [degrees]C are presented in figure 6.Chrystal. Nirvana Seed Bank. Indica 60 / Sativa 40 Origins: White Widow x Northern Lights Flowering: days Harvest: early October.

Chrystal is a child of celbrity parents, destined for her own renown. The Chrystal mother derives from the legendary White Widow strain.

White Widow set the standard for “White” weed strains. Nirvana’s.Tamura, Mori and Nakamura reported finding serrated yielding in Al-3 wt.% Li single crystals deformed at room temperature at a strain rate near 10/sup -3/ 5/sup -1/.

However, similar polycrystalline samples did not exhibit serrated yielding, a observation which Tamura et al ascribed to interference of the primary slip system by grain boundaries.