Deconvoluting error in measurement of low angle misorientation distribution

A calculation method for obtaining the misorientation distribution function (MDF) for cubic crystals which can be used to estimate the presence or absence of special boundaries in the materials is presented. The calculation was carried out for two samples of Al-Mg-Si alloy subjected to various mechanical and thermal treatments: the first sample is subjected to rolling; the second sample is subjected to recrystallization annealing. MDF is calculated for each sample; the results are presented in the Euler space and in the angle-axis space. The novelty of the method consists in the possibility of gaining data on the grain boundaries from X-ray texture analysis without using electron microscopy. A calculation involving only mathematical operations on matrices was performed on the basis of the orientation distribution function restored from incomplete pole figures. It is shown that no special boundaries are observed in the deformed sample, whereas in the recrystallized alloy, special boundaries are detected at Ʃ = 23, 13, and 17. The shortcoming of the proposed method can be attributed to the lack of accurate data on grain boundaries, since all possible orientation in the polycrystal should be taken into account in MDF calculation.

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Ultra Grain Refinement of Low C Steels by Accumulative Roll Bonding

Materials Science Forum ◽

10.4028/www.scientific.net/msf.503-504.311 ◽

2006 ◽

Vol 503-504 ◽

pp. 311-316 ◽

Cited By ~ 1

Author(s):

I. Salvatori

Keyword(s):

Accumulative Roll Bonding ◽

Orientation Imaging Microscopy ◽

Low Carbon Steel ◽

Small Samples ◽

Low Carbon ◽

High Angle ◽

Misorientation Distribution ◽

Roll Bonding ◽

Orientation Imaging ◽

Annealing Conditions

Refinement of grain size is one of the biggest challenges to produce steels with improved combination of strength and toughness. Ultrafine structures are being produced world-wide on various materials, including low carbon steel, using different types of processes. However, the majority of these processes also exhibit severe limitations because they are generally restricted to small samples and are difficult to be implemented on an industrial scale. A promising technique for industrial implementation is the Accumulative Roll Bonding (ARB), a process able to supply large samples, even in the laboratory scale. In this paper, warm intense straining (ε = 4) by ARB was applied to a plain low-C steel in order to develop ultrafine grains, aiming at sizes around 1-2 μm, suitable to maintain an adequate combination of strength and ductility. The effect of annealing conditions on the evolution of the work-hardened microstructure and the bonding behaviour after each pass were investigated. Orientation Imaging Microscopy was used to investigate the microstructure and give a quantitative assessment of high angle and low angle boundaries. It is showed that the frequency of high angle grain boundaries increases with the strain but the misorientation distribution remained far from that typical of a recrystallised material.

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Effect of Thermomechanical Processing on Grain Size, Texture and Mechanical Properties of Pure Magnesium

Materials Science Forum ◽

10.4028/www.scientific.net/msf.985.97 ◽

2020 ◽

Vol 985 ◽

pp. 97-108

Author(s):

Mouhamadou Moustapha Sarr ◽

Motohiro Yuasa ◽

Hiroyuki Miyamoto

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

Yield Stress ◽

Thermomechanical Processing ◽

Pure Magnesium ◽

Grain Structure ◽

Misorientation Distribution ◽

Processed Material ◽

Texture Characterization

This study aims to investigate the effect of processing routes (A and Bc) and temperature on microstructure, texture and mechanical properties of pure magnesium was studied in this research. An extruded pure magnesium (~99,9 %) was subjected to severe plastic deformation (SPD) by ECAP. Deformation was conducted at 523K and 473K and two different processing routes (A and Bc) were used to control the texture. The microstructure and texture characterization of the pressed materials were carried out. It was found that the microstructure displayed a bimodal grain structure after two passes and then became homogeneous after four passes following both routes A and Bc. The misorientation distribution was examined and the results revealed that the fraction of high angle grain boundaries (HAGB) was higher at temperature 473K. The texture was randomized following route Bc whereas it became strengthened in route A after four passes. According to the Hall-Petch (HP) relationship, the yield stress of polycrystalline metals increases with a decrease in grain size. In this study, a positive slope k was achieved in the strengthened texture while a negative one was obtained in the softened texture. The ductility of ECAP processed material was considerably improved (from 23% to 38%) without sacrificing the yield stress by route Bc at 423K.

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The preferred CSL misorientation distribution in polycrystalline SrTiO3

Journal of Microscopy ◽

10.1111/j.1365-2818.2007.01813.x ◽

2007 ◽

Vol 227 (3) ◽

pp. 292-297 ◽

Cited By ~ 5

Author(s):

MYUNG-BEOM PARK ◽

SHAO-JU SHIH ◽

DAVID J. H. COCKAYNE

Keyword(s):

Misorientation Distribution

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Microstructural Characterization of Friction-Stir Processed Ti-6Al-4V

Metals ◽

10.3390/met10070976 ◽

2020 ◽

Vol 10 (7) ◽

pp. 976 ◽

Cited By ~ 1

Author(s):

Sergey Mironov ◽

Yutaka S. Sato ◽

Hiroyuki Kokawa ◽

Satoshi Hirano ◽

Adam L. Pilchak ◽

...

Keyword(s):

Electron Backscatter Diffraction ◽

Microstructural Characterization ◽

Mechanical Twinning ◽

High Temperature Deformation ◽

Temperature Deformation ◽

Misorientation Distribution ◽

Friction Stir ◽

Α Phase ◽

Ebsd Technique ◽

Backscatter Diffraction

The present work was undertaken to shed additional light on the globular-α microstructure produced during FSP of Ti-6Al-4V. To this end, the electron backscatter diffraction (EBSD) technique was employed to characterize the crystallographic aspects of such microstructure. In contrast to the previous reports in the literature, neither the texture nor the misorientation distribution in the α phase were random. Although the texture was weak, it showed a clear prevalence of the P1 and C-fiber simple-shear orientations, thus providing evidence for an increased activity of the prism-<a> and pyramidal <c+a> slip systems. In addition, the misorientation distribution exhibited a crystallographic preference of 60° and 90° boundaries. This observation was attributed to a partial α→β→α phase transformation during/following high-temperature deformation and the possible activation of mechanical twinning.

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On the correlation of grain boundary misorientation distribution with critical current in bulk processed YBa2Cu3O7-δ

Philosophical Magazine A ◽

10.1080/01418619808239972 ◽

1998 ◽

Vol 78 (5) ◽

pp. 1037-1049 ◽

Cited By ~ 3

Author(s):

Jenn-Yue Wang ◽

Alexander H. King ◽

Yimei Zhu ◽

Yuan-Liang Wang ◽

Masaki Suenaga

Keyword(s):

Grain Boundary ◽

Critical Current ◽

Boundary Misorientation ◽

Misorientation Distribution ◽

Grain Boundary Misorientation

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Effect of Initial Texture on the Deformed Microstructure of IF Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.558-559.1395 ◽

2007 ◽

Vol 558-559 ◽

pp. 1395-1400

Author(s):

Jun Yun Kang ◽

Brigitte Bacroix ◽

Kyu Hwan Oh ◽

Hu Chul Lee

Keyword(s):

Texture Evolution ◽

Rolling Texture ◽

Small Strain ◽

Deformation Texture ◽

Fiber Texture ◽

Orientation Dependence ◽

If Steel ◽

Misorientation Distribution ◽

Steel Sheets ◽

Initial Texture

The development of deformation texture and microstructure was examined for four different initial textures. IF steel sheets with a majority of α-, ε-, and γ-fiber and near random texture were prepared and cold rolled. The specimens exhibited characteristic behaviors in rolling texture evolution and deformation-induced misorientation development, according to their initial textures, especially at small strain levels. Due to the orientation dependence of intra-granular misorientation accumulation, the different texture evolutions affected the induced misorientation distribution. A larger fraction of γ-fiber orientations was related to more prominent misorientation development, while the initial texture stability simultaneously affected the misorientation development. The unstable, initial ε-fiber texture showed a stronger tendency of misorientation accumulation than the stable α-fiber during the subsequent cold rolling.

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