An Analysis of Microband Orientation in Hot Deformed Aluminium Alloy AA5052 Using Forward and Reverse Torsion

2006 ◽  
Vol 519-521 ◽  
pp. 877-882
Author(s):  
M. Lopez-Pedrosa ◽  
Bradley P. Wynne ◽  
Mark W. Rainforth ◽  
P. Cizek
Keyword(s):  
Strain Path ◽  
Electron Backscatter Diffraction ◽  
Principal Strain ◽  
The Maximum Principle ◽  
Stress Direction ◽  
Resolution Electron ◽  
Macroscopic Deformation ◽  
Backscatter Diffraction ◽  
Macroscopic Orientation ◽  
Strain Direction

The effects of strain path reversal on the macroscopic orientation of microbands in AA5052 have been studied using high resolution electron backscatter diffraction. Deformation was carried using two equal steps of forward/forward or forward/reverse torsion at a temperature of 300°C and strain rate of 1s-1 to a total equivalent tensile strain of 0.5. In both cases microbands were found in the majority of grains examined with many having more than one set. The microbands appear to cluster at specific angles to the macroscopic deformation. For the forward/forward condition microbands clustered around -20° and +45° to the maximum principle stress direction and at ± 30-35° to the principal strain direction. For the forward/reverse condition significantly more spread in microband angle was observed though peaks were visible at ±35° with respect to principal stress direction and at -40° and +30° with respect to the principal strain direction of the reverse torsion. This suggests the microbands formed in the forward deformation have or are dissolving and any new microbands formed are related to the deformation conditions of the final strain path.

An Analysis of Strain Path Effects on Static Recrystallisation in Hot Worked Aluminium Alloy AA5052 Using Forward and Reverse Torsion

2007 ◽  
Vol 558-559 ◽  
pp. 407-412 ◽  
Author(s):  
Bradley P. Wynne ◽  
O. Hernandez-Silva ◽  
M. Lopez-Pedrosa ◽  
Mark W. Rainforth
Keyword(s):  
Aluminium Alloy ◽  
Strain Path ◽  
Electron Backscatter Diffraction ◽  
Cell Structure ◽  
Salt Bath ◽  
Dislocation Cell ◽  
Major Effect ◽  
Deformation Substructure ◽  
Resolution Electron ◽  
Backscatter Diffraction

The effects of strain path reversal, using forward and reverse torsion, on the microstructure evolution in the aluminium alloy AA5052 have been studied using high resolution electron backscatter diffraction. Deformation was carried using two equal steps of forward/forward or forward/reverse torsion at a temperature of 300°C and strain rate of 1s-1 to a total equivalent tensile strain of 0.5. Sections of the as-deformed gauge lengths of both test specimens were then annealed at 400°C for 1 hour in a salt bath in order to investigate their subsequent recrystallisation response. In both strain path histories the deformation substructure in the grains analysed consisted of microband arrays within an equiaxed dislocation cell structure. The material subjected to forward/forward deformation did, however, have a slightly greater number of low angle boundaries, i.e. boundaries < 15° misorientation, whilst the forward/reverse material had some grains containing little evidence of substructure. On annealing both materials had significantly reduced levels of low angle boundaries but only the forward/forward material had an increased number of high angle boundaries and a reduced grain size, indicating recrystallisation had only occurred in this material. This would suggest that the deformation microstructure within the forward/forward condition was sufficient to initiate and maintain recrystallisation whilst the microstructure produced by the forward/reverse test contained insufficient nuclei or internal energy to produce a recrystallised material within 1 hour. Further work is now required at different annealing times in order to determine if the major effect of strain path is on retarding nucleation, growth or both.

scholarly journals Correlation of Strain Path, Texture, Twinning, and Mechanical Properties in Twinning-Induced Plasticity Steel during Wire Drawing

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2250 ◽  
Author(s):  
Joong-Ki Hwang
Keyword(s):  
Mechanical Properties ◽  
Strain Path ◽  
Electron Backscatter Diffraction ◽  
Steel Wire ◽  
Effective Strain ◽  
Metal Flow ◽  
Wire Drawing ◽  
Surface Areas ◽  
The Wire ◽  
Backscatter Diffraction

The effect of changing the strain path on texture development, twin kinetics, and mechanical properties in twinning-induced plasticity steel was investigated to understand twinning behavior in more detail. Among the various plastic deformation processes, the wire drawing process was selected to achieve the aims of the study. Specimens of cold-drawn TWIP steel wire under the same effective strain but with different crystallographic textures were successfully fabricated using the effect of the wire drawing direction. Electron backscatter diffraction results showed that the drawn wires using both unidirectional (UD) and reverse-directional (RD) wire drawing processes were characterized as duplex fiber textures of major <111> and minor <100>. It was found that the RD wire had a higher fraction of <111> component at both the center and surface areas compared to the UD wire, because the metal flow of the RD wire was beneficial for the development of a <111> orientation. The pronounced <111> crystallographic orientation of the RD wire activated the twinning rate and geometrically necessary dislocation density, leading to an increase in strength but a decrease in ductility. The strain path is as important as the amount of strain for strengthening the materials, especially those that are deformed by twinning.

3D-EBSD Studies of Deformation, Recrystallization and Phase Transformations

2012 ◽  
Vol 715-716 ◽  
pp. 41-50 ◽  
Author(s):  
Michael Ferry ◽  
Wan Qiang Xu ◽  
M. Zakaria Quadir ◽  
Nasima Afrin Zinnia ◽  
Kevin J. Laws ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Thermomechanical Processing ◽  
Electron Backscatter Diffraction ◽  
Ion Beam ◽  
Void Formation ◽  
Data Generation ◽  
Serial Sectioning ◽  
Resolution Electron ◽  
Plastic Forming ◽  
Backscatter Diffraction

A focused ion beam (FIB) coupled with high resolution electron backscatter diffraction (EBSD) has emerged as a useful tool for generating crystallographic information in reasonably large volumes of microstructure. In principle, data generation is reasonably straightforward whereby the FIB is used as a high precision serial sectioning device for generating consecutive milled surfaces suitable for mapping by EBSD. The successive EBSD maps generated by serial sectioning are combined using various post-processing methods to generate crystallographic volumes of the microstructure. This paper provides an overview of the use of 3D-EBSD in the study of various phenomena associated with thermomechanical processing of both crystalline and semi-crystalline alloys and includes investigations on the crystallographic nature of microbands, void formation at particles, phase redistribution during plastic forming, and nucleation of recrystallization within various regions of the deformation microstructure.

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