A Study on Characteristics of Microstructures and Orientations of UFG Materials Prepared by SPD

2010 ◽  
Vol 667-669 ◽  
pp. 343-347 ◽  
Author(s):  
Qing Nan Shi ◽  
Yong Jin Chen ◽  
Jun Li Wang
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Severe Plastic Deformation ◽  
Shear Deformation ◽  
Pure Copper ◽  
Grain Refining ◽  
X Ray Diffraction ◽  
6061 Aluminum Alloy ◽  
X Ray ◽  
Deformation Processes

In the paper, the study was conducted on the characteristics of microstructures and orientations of UFG pure copper and 6061 aluminum alloy prepared by AARB, ECAP and CECC severe plastic deformation processes, in which SEM, TEM, EBSD and X-ray diffraction techniques were employed. The result of the study shows that microstructures, mainly composed of subgrains and dislocation kinks, are profuse in the UFG materials by the three SPDs. These kinds of microstructures have the strength of the materials much enhanced and the toughness heavily decreased. In these processes, shear deformation makes gains get finer and finer with the existence of the preferred orientations in the prepared UFG materials. Nevertheless, CECC shows the heaviest effect on the grain refining and the preferred orientation weakening.

Influence of Severe Plastic Deformation on Physicomechanical Properties of Ti-40 mas % Nb Alloy

2016 ◽  
Vol 685 ◽  
pp. 525-529
Author(s):  
Zhanna G. Kovalevskaya ◽  
Margarita A. Khimich ◽  
Andrey V. Belyakov ◽  
Ivan A. Shulepov
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Cold Working ◽  
Young Modulus ◽  
Physicomechanical Properties ◽  
X Ray Diffraction ◽  
Refined Grains ◽  
X Ray ◽  
Initial Alloy ◽  
Composition Structure

The changes of the phase composition, structure and physicomechanical properties of Ti‑40 mas % Nb after severe plastic deformation are investigated in this paper. By the methods of microstructural, X-ray diffraction analysis and scanning electron microscopy it is determined that phase and structural transformations occur simultaneously in the alloy after severe plastic deformation. The martensitic structure formed after tempering disappears. The inverse α'' → β transformation occurs. The structure consisting of oriented refined grains is formed. The alloy is hardened due to the cold working. The Young modulus is equal to 79 GPa and it is less than that of initial alloy and close to the value obtained after tempering. It is possible that Young modulus is reduced by additional annealing.

Texture Development in a Model Al-Li Alloy Subjected to Severe Plastic Deformation

2006 ◽  
Vol 114 ◽  
pp. 337-344 ◽  
Author(s):  
Bogusława Adamczyk-Cieślak ◽  
Jaroslaw Mizera ◽  
Krzysztof Jan Kurzydlowski
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Extrusion ◽  
Orientation Distribution ◽  
X Ray Diffraction ◽  
Technological Parameters ◽  
Initial State ◽  
Texture Characteristic ◽  
X Ray ◽  
Ultrafine Grained

The texture of Al – 0.7 wt. % Li alloy processed by two different methods of severe plastic deformation (SPD) has been investigated by X-ray diffraction, and analyzed in terms of the orientation distribution function (ODF). It was found that severe plastic deformation by both Equal Channel Angular extrusion (ECAE) and Hydrostatic Extrusion (HE) resulted in an ultrafine grained structure in an Al – 0.7 wt. % Li alloy. The microstructure, grain shape and size, of materials produced by SPD strongly depend on the technological parameters and methods applied. The texture of the investigated alloy differed because of the different modes of deformation. In the initial state the alloy exhibited a very strong texture consisting of {111} fibre component. A similar fibrous texture characteristic was also found after HE whereas after the ECAE the initial texture was completely changed.

Probing properties of 6061 aluminum alloy used as cladding for nuclear reactor fuel with X-ray diffraction

2020 ◽  
Author(s):  
Mahmoud H. Abd-Elhakim ◽  
Mostafa Mostafa ◽  
Mostafa Darwash ◽  
M. Abdel-Rahman ◽  
M. A. Abdel-Rahman ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Nuclear Reactor ◽  
Reactor Fuel ◽  
X Ray Diffraction ◽  
6061 Aluminum Alloy ◽  
X Ray ◽  
Nuclear Reactor Fuel

Prediction of the Stress-Strain Response of the Ultrafine-Grained Materials Using Multi-Scale Analysis

2010 ◽  
Author(s):  
Mihaela Banu ◽  
Mitica Afteni ◽  
Alexandru Epureanu ◽  
Valentin Tabacaru
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Aluminum Alloy ◽  
Severe Plastic Deformation ◽  
Scale Analysis ◽  
Multi Scale ◽  
Ultrafine Grained ◽  
Deformation Processes ◽  
Ultrafine Grained Materials ◽  
Multi Scale Analysis

There are several severe plastic deformation processes that transform the material from microsized grains to the nanosized grains under large deformations. The grain size of a macrostructure is generally 300 μm. Following severe plastic deformation it can be reached a grain size of 200 nm and even less up to 50 nm. These structures are called ultrafine grained materials with nanostructured organization of the grains. There are severe plastic deformation processes like equal angular channel, high pressure torsion which lead to a 200 nm grain size, respectively 100 nm grain size. Basically, these processes have a common point namely to act on the original sized material so that an extreme deformation to be produced. The severe plastic deformation processes developed until now are empirically-based and the modeling of them requires more understanding of how the materials deform. The macrostructural material models do not fit the behavior of the nanostructured materials exhibiting simultaneously high strength and ductility. The existent material laws need developments which consider multi-scale analysis. In this context, the present paper presents a laboratory method to obtain ultrafine grains of an aluminum alloy (Al-Mg) that allows the microstructure observations and furthermore the identification of the stress–strain response under loadings. The work is divided into (i) processing of the ultrafine-grained aluminum alloy using a laboratory-scale process named in-plane controlled multidirectional shearing process, (ii) crystallographic analysis of the obtained material structure, (iii) tensile testing of the ultrafine-grained aluminum specimens for obtaining the true stress-strain behavior. Thus, the microscale phenomena are explained with respect to the external loads applied to the aluminum alloy. The proposed multi-scale analysis gives an accurate prediction of the mechanical behavior of the ultrafine-grained materials that can be further applied to finite element modeling of the microforming processes.

Severe Plastic Deformation of a Bainitic Rail Steel

2008 ◽  
Vol 584-586 ◽  
pp. 655-660 ◽  
Author(s):  
Anton Hohenwarter ◽  
Richard Stock ◽  
Reinhard Pippan
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Severe Plastic Deformation ◽  
Retained Austenite ◽  
High Pressures ◽  
Rail Steel ◽  
Fatigue Cracks ◽  
Shear Direction ◽  
X Ray Diffraction ◽  
X Ray

Severe Plastic Deformation (SPD) is known to be an effective method of producing nanocrystalline materials, for instance by HPT and ECAP. These techniques are also capable of reproducing microstructures which arise naturally when high pressure and friction is involved, for example in wheel-rail contact problems. The resulting deformation layers build the origin point for fatigue cracks. For that reason the knowledge of the mechanical properties of these deformation layers are of vital importance. In the framework of this study a baintic rail steel quality was deformed by High Pressure Torsion up to distinctive equivalent strains at a nominal pressure of 6 GPa up to a final equivalent strain of 16. Afterwards the evolution of the resulting microstructure was investigated by Scanning Electron Microscopy, by microhardness measurements and X-ray diffraction. The bainitic structure showed a strong alignment and fragmentation into the shear direction with increasing strain, which was accompanied by an increase in hardness as well. X-ray diffraction measurements showed that the amount of retained austenite decreases dramatically after small amounts of strain, which indicates that retained austenite cannot be stabilized by high pressures. Torque measurements during deformation showed after strong hardening at the beginning, a saturation behaviour for higher strains, whereas for instance pearlitic rail steel qualities show further hardening.

Improvement in Drawability (r Value) of an Aluminum Alloy Subjected to Groove Pressing

2010 ◽  
Vol 638-642 ◽  
pp. 1911-1916
Author(s):  
Ganesh Niranjan ◽  
Chakkingal Uday
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Rolling Direction ◽  
Al Alloy ◽  
Drawing Ratio ◽  
X Ray Diffraction ◽  
Shear Texture ◽  
Planar Anisotropy ◽  
Normal Anisotropy ◽  
X Ray

There is increasing interest in using Al alloy sheets for auto body applications. However Al alloys exhibit poor drawability as indicated by low values of the normal anisotropy, rm. Techniques for improving the value of rm rely on developing a favourable shear texture in the sheet. In this study, Al alloy AA 6061 sheets of dimensions 225 mm x 200 mm and 1 mm thick were subjected to severe plastic deformation by repeated groove pressing using a set of grooved and flat dies alternatively. The orientation of the grooves with respect to the rolling direction was also varied. Microstructure characterization and mechanical property measurements were carried out. X- ray diffraction scans were carried out to measure the relative intensities of the (111) and (200) peaks. The r values was measured as per ASTM standard E 517 on strip specimens cut at 0°, 45° and 90° to the rolling direction and the normal anisotropy value (rm) and planar anisotropy value (Δr) values were determined. The limiting drawing ratio (LDR) was determined using the Swift cupping test techniques. It was observed that the rm values increased from 0.72 in the as received condition to a maximum of 0.94 and the LDR increased from 1.93 to 2.06 when the groove pressing was carried out with grooves at to 45° the rolling direction. The improvement in rm values can be correlated to the texture developing in the sheet as a result of severe plastic deformation.

Microstructural Changes during Precision Machining of Thin Substrates

2010 ◽  
Vol 447-448 ◽  
pp. 76-80
Author(s):  
K. Saptaji ◽  
Subbiah Sathyan
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Crystallographic Orientation ◽  
High Ratio ◽  
Machining Process ◽  
Deformation Mechanisms ◽  
Precision Machining ◽  
Depth Of Cut ◽  
X Ray Diffraction ◽  
X Ray

This paper reports investigations in machining of thin substrates with thickness less than 100m. The machining process induces severe plastic deformation through the thickness of the machined thin workpiece due to the high ratio of the depth of cut to workpiece thickness. The diamond face turning is used to machine thin workpieces down to a thickness less than 100m. The microstructure of the machined sample is studied and x-ray diffraction used to observe the crystallographic orientation / texture. The microstructures of the thin machined workpieces are seen to become more random, denser, and finer with the shape of the grains less elongated as compare to the bulk and thick machined sample. The x-ray diffraction analyses indicate that machining of thin substrates changes the texture or orientation. Different deformation mechanisms may occur when machining thin workpiece especially at thicknesses below 100m.

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