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

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.

Author(s):  
Yong Huang ◽  
Mason Morehead

Various methods for the production of bulk nanostructured (NS)/ultrafine-grained (UFG) materials have been developed, including equal channel angular extrusion (ECAE), a form of severe plastic deformation. Using an ECAE NS/UFG copper bar as an example, this study has investigated machining-induced workpiece microstructure variation using X-ray diffraction. It has been found that (1) under gentle cutting conditions, there was a 10% increase in the median grain size compared with unmachined ECAE NS/UFG copper bars. Increases in the arithmetic-, area-, and volume-weighted grain sizes were found to be 10%, 8%, and 8%, respectively, and (2) an average 27% drop in the dislocation density was observed between the machined and unmachined ECAE copper bars. The dislocation density was shown to have the most reduction (−39%) at the outer radius of the machined ECAE bar where more heat and/or higher pressure were experienced.


2016 ◽  
Vol 685 ◽  
pp. 525-529
Author(s):  
Zhanna G. Kovalevskaya ◽  
Margarita A. Khimich ◽  
Andrey V. Belyakov ◽  
Ivan A. Shulepov

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.


2008 ◽  
Vol 584-586 ◽  
pp. 655-660 ◽  
Author(s):  
Anton Hohenwarter ◽  
Richard Stock ◽  
Reinhard Pippan

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.


2010 ◽  
Vol 638-642 ◽  
pp. 1911-1916
Author(s):  
Ganesh Niranjan ◽  
Chakkingal Uday

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.


2010 ◽  
Vol 447-448 ◽  
pp. 76-80
Author(s):  
K. Saptaji ◽  
Subbiah Sathyan

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.


2011 ◽  
Vol 682 ◽  
pp. 65-70 ◽  
Author(s):  
Hong Jiang ◽  
Chao Ying Xie ◽  
Jie Song ◽  
Xiao Gang Sun ◽  
Xiao Ning Zhang

Ultrafine-grained (UFG) commercial pure (CP, grade 3) Ti was produced by two-step severe plastic deformation (eight-pass equal channel angular extrusion (ECAE) at 400 °C and cold rolling (CR) at room temperature (RT)). The crystallographic texture in UFG CP-Ti and coarse-grained (CG) CP-Ti (annealed) after CR at RT are studied by orientation distribution function (ODF) analysis, based on X-ray diffraction. The relationship between the texture components and mechanical properties of UFG CP-Ti after two-step severe plastic deformation (SPD) has been discussed. ODF analysis shows that the main texture components in UFG Ti after CR at RT are (011—5)[11— 01], (011—5)[22—01], (0001)[1—3—43] and (011—3)[21—1—1], while the texture components of (011—3)[1—101—] and (011— 3)[2— 201] appear in CG CP-Ti after CR at RT. The values of Schmid factor for prismatic-<a> slip systems are larger than that for basal<a> slip systems and other slip systems, which is more in favor of the activation of prismatic-<a>. In addition, higher strength of texture in favor of the activation of prismatic-<a> in UFG CP-Ti improves its plasticity.


2014 ◽  
Vol 635 ◽  
pp. 18-21 ◽  
Author(s):  
Petra Lacková ◽  
Ondrej Milkovič ◽  
Marián Buršák ◽  
Tibor Kvačkaj

The effect of severe plastic deformation by ECAP process on the microstructures and mechanical properties of the aluminium alloy EN AW 6082 produced by cold extrusion is investigated. In both states were evaluated the structural changes by light microscopy, the analysis particles in structures, by X-ray diffraction (XRD) in transmission mode by synchrotron radiation and mechanical properties. Severe plastic deformation leads to strengthening of investigated EN AW 6082 alloy but on the other hand the plasticity of ECAP-ed alloy decreases.


Author(s):  
Lembit Kommel

The purpose of this study is to X-ray line-profile analysis of the effect of rapid Joule heating and severe plastic deformation concurrently on microstructure and properties evolution in polycrystalline austenitic Fe-balanced superalloy EP718E, which is Inconel 718 derivative. The microstructure of superalloy at different stages of processing was examined by X-ray diffraction, by scanning electron microscopy, and by energy dispersive spectrometry techniques. The mechanical properties of evolution were studied by means of tension and high cycle fatigue testings. The results of X-ray study show that the intensity, raw areas, and net areas were a step–by–step changed according to processing routines. Is shown that under shear stress the fcc-crystallites were deformed and the peaks parameters by 2-Theta scale changed partly.


Author(s):  
Lembit Kommel ◽  
R. Traksmaa ◽  
V. Mikli

The purpose of this study is to X-ray line-profile analysis of the effect of rapid Joule heating and severe plastic deformation concurrently on microstructure and properties evolution in polycrystalline austenitic Fe-balanced superalloy EP718E, which is Inconel 718 derivative. The microstructure of superalloy at different stages of processing was examined by X-ray diffraction, by scanning electron microscopy, and by energy dispersive spectrometry techniques. The mechanical properties of evolution were studied by means of tension and high cycle fatigue testings. The results of X-ray study show that the intensity, raw areas, and net areas were a step–by–step changed according to processing routines. Is shown that under shear stress the fcc-crystallites were deformed and the peaks parameters by 2-Theta scale changed partly.


Sign in / Sign up

Export Citation Format

Share Document