Ultra Fine-Grained Metals Prepared by Severe Plastic Deformation: A Positron Annihilation Study
نویسندگان
چکیده
منابع مشابه
Superplasticity of a fine-grained Mg–1.5 wt% Gd alloy after severe plastic deformation
The strain rate sensitivity (SRS) of Mg–1.5 wt% Gd processed by conventional extrusion and 2 passes of simple shear extrusion (SSE) was investigated by shear punch testing. Shear punch tests were conducted at initial shear strain rates in the range of 0.003–0.3 s-1 and at temperatures in the range of 573–773 K. A fine-grained microstructure with an average grain size of about 2.5 µm, obtained a...
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1 List of symbols and abbreviations 3 Chapter 1: INTRODUCTION 6 Chapter 2: LITERATURE SURVEY 8 2.1: The essence of ultra fine grained materials 8 2.2: Severe plastic deformation: a method for producing UFG microstructure 11 2.3: Physical properties of materials derived from GB character 15 2.4: Non-equilibrium GBs: theoretical aspects 16 2.4.1: Conventional models for GB structure 16 2.4.2: Mod...
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This paper provides an introduction in the field of severe plastic deformation (SPD). First of all the main methods to produce SPD materials are discussed. In the following section, the mechanisms leading to the formation of fine grains are reviewed and the influence of changes in strain path is highlighted. During post-SPD thermal annealing, some typical microstructural changes take place. The...
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In this paper, cyclic flaring and sinking (CFS) as a new severe plastic deformation (SPD) method was employed to produce the ultrafine grain (UFG) copper tubes. The extra friction has eliminated in the CFS method that provided the possibility for production of longer UFG tubes compared to the other SPD methods. This process was done periodically to apply more strain and consequently finer grain...
متن کاملStructure and Mechanical Properties of Nanostructured Metals Prepared by Severe Plastic Deformation
Ultrafine-grained (UFG) nanostructured materials having grain sizes of tens and hundreds of nanometers recently have aroused interest among researchers in the materials science field. With respect to their mechanical properties, one would hope to be able to obtain the extremely strong states that can be expected in the case of strong grain refinement according to the Hall-Petch relationship (Gl...
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ژورنال
عنوان ژورنال: Acta Physica Polonica A
سال: 2005
ISSN: 0587-4246,1898-794X
DOI: 10.12693/aphyspola.107.745