Texture Evolution of HPT-Processed Ni50Mn29Ga21

2011 ◽  
Vol 702-703 ◽  
pp. 169-172 ◽  
Author(s):  
Robert Chulist ◽  
Andrea Böhm ◽  
E. Rybacki ◽  
T. Lippmann ◽  
C.G. Oertel ◽  
...  
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Synchrotron Radiation ◽  
High Pressure Torsion ◽  
Electron Backscatter Diffraction ◽  
Texture Evolution ◽  
Residual Austenite ◽  
High Energy ◽  
Electron Backscatter ◽  
Backscatter Diffraction

The texture of polycrystalline Ni50Mn29Ga21alloys fabricated by high pressure torsion (HPT) was investigated with high-energy synchrotron radiation. HPT was performed at temperatures between 873K and 1173K under a hydrostatic pressure of 400 MPa. During HPT above 973K the initial cyclic fibre texture changes to a strong cube and a weak F component. Below 973K a strong rotated cube and weak F and C components develop. Additionally, electron backscatter diffraction reveals that samples deformed at low temperature do not completely transform to martensite giving rise to residual austenite.

Peculiarities in the Texture Formation of Intermetallic Compounds Deformed by High Pressure Torsion

2014 ◽  
Vol 1760 ◽  
Author(s):  
Christine Tränkner ◽  
Aurimas Pukenas ◽  
Jelena Horky ◽  
Michael Zehetbauer ◽  
Werner Skrotzki
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Electron Backscatter Diffraction ◽  
High Energy ◽  
X Ray ◽  
Local Texture ◽  
Large Rotations ◽  
Electron Backscatter ◽  
Shear Strains ◽  
Backscatter Diffraction

ABSTRACTNiAl, YCu and TiAl polycrystals with B2 and L10 structure, respectively, have been deformed by high pressure torsion (HPT) at temperatures between 20°C and 500°C at a hydrostatic pressure of 8 GPa to high shear strains. Local texture measurements were done by diffraction of high-energy synchrotron radiation and X-ray microdiffraction. In addition, the microstructure was analyzed by electron backscatter diffraction (EBSD). Besides typical shear components an oblique cube component is observed with quite large rotations about the transverse direction. Based on the temperature dependence of this component as well as on microstructure investigations it is concluded that it is formed by discontinuous dynamic recrystallization. The influence of high pressure on recrystallization of intermetallics at low temperatures is discussed.

An Investigation of Microtexture Evolution in an AlMgSi Alloy Processed by High-Pressure Torsion

2011 ◽  
Vol 702-703 ◽  
pp. 165-168 ◽  
Author(s):  
Aicha Loucif ◽  
Thierry Baudin ◽  
François Brisset ◽  
Roberto B. Figueiredo ◽  
Rafik Chemam ◽  
...  
Keyword(s):  
Grain Size ◽  
High Pressure ◽  
Distribution Function ◽  
High Pressure Torsion ◽  
Electron Backscatter Diffraction ◽  
Orientation Distribution ◽  
Homogeneous Microstructure ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Almgsi Alloy

This investigation uses electron backscatter diffraction (EBSD) to study the development of microtexture with increasing deformation in an AlMgSi alloy having an initial grain size of about 150 µm subjected to high pressure torsion (HPT) up to a total of 5 turns. An homogeneous microstructure was achieved throughout the disc sample at high strains with the formation of ultra-fine grains. Observations based on orientation distribution function (ODF) calculation reveals the presence of the torsion texture components often reported in the literature for f.c.c. materials. In particular, the C {001}<110> component was found to be dominant. Furthermore, no significant change in the texture sharpness was observed by increasing the strain.

Role of Texture in Understanding Creep Flow in HPT-Processed Ultrafine Grained Copper

2011 ◽  
Vol 702-703 ◽  
pp. 370-373
Author(s):  
Jörn Leuthold ◽  
Matthias Wegner ◽  
Sergiy V. Divinski ◽  
K. Anantha Padmanabhan ◽  
Daria Setman ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Electron Backscatter Diffraction ◽  
Tensile Elongation ◽  
Tensile Creep ◽  
Creep Flow ◽  
Ultrafine Grained ◽  
Electron Backscatter ◽  
Backscatter Diffraction

Disks of copper samples were produced by High Pressure Torsion (HPT). Specimens for tensile creep experiments were cut from the disks and subjected to creep deformation at 348 K to obtain elongations greater than 30%. Electron backscatter diffraction (EBSD) was used to analyze the texture after HPT deformation and after additional tensile elongation.

scholarly journals Twinning Behaviour of Textured Polycrystalline Ni-Mn-Ga Alloy after Hot Extrusion

2009 ◽  
Vol 635 ◽  
pp. 195-199 ◽  
Author(s):  
Robert Chulist ◽  
Andrea Böhm ◽  
Thomas Lippmann ◽  
Werner Skrotzki ◽  
Welf Guntram Drossel ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Single Crystals ◽  
Electron Backscatter Diffraction ◽  
Extrusion Direction ◽  
Hot Extrusion ◽  
High Energy ◽  
Fibre Texture ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Martensitic Variants

Up to now most of the research on Ni-Mn-Ga alloys was concentrated on single crystals. However, there is a great interest in polycrystals for technical applications. Recently, polycrystalline Ni50Mn29Ga21 rods of 25 mm diameter and 400 mm length were prepared by hot extrusion. The <100> <110> double fibre texture of the extruded rods was measured with high-energy synchrotron radiation. The microstructure after hot extrusion was analyzed with electron backscatter diffraction. Within the recrystallized grains all three martensitic variants have developed during cooling. Variants with twin boundaries preferentially aligned along the extrusion direction predominate.

Texture and Microstructure Evolution in Friction Stir Welded Cu-Al Sheets Characterized by EBSD

2011 ◽  
Vol 702-703 ◽  
pp. 574-577 ◽  
Author(s):  
Daniel Goran ◽  
G. Ji ◽  
M. N. Avettand-Fènoël ◽  
R. Taillard
Keyword(s):  
Microstructure Evolution ◽  
Electron Backscatter Diffraction ◽  
Texture Evolution ◽  
Weld Interface ◽  
Friction Stir ◽  
Electron Backscatter ◽  
Ebsd Technique ◽  
Backscatter Diffraction

Texture and microstructure of FSW joined Al and Cu sheets were investigated by means of electron backscatter diffraction (EBSD) technique. The analysis has revealed a strong texture evolution on both sides of the weld interface as well as a very complex microstructure. Grains were found to be fully recrystallized on both sides of the weld and with different average diameters at different specific zones of the weld.

Influence of Temperature upon the Texture Evolution and Mechanical Behaviour of Zircaloy-4

2011 ◽  
Vol 702-703 ◽  
pp. 834-837
Author(s):  
Peter Honniball ◽  
Michael Preuss ◽  
Joao Quinta da Fonseca
Keyword(s):  
Mechanical Behaviour ◽  
Room Temperature ◽  
Electron Backscatter Diffraction ◽  
Texture Evolution ◽  
Crystal Plasticity Finite Element ◽  
Ebsd Data ◽  
Electron Backscatter ◽  
Different Temperatures ◽  
Increasing Temperature ◽  
Backscatter Diffraction

The mechanical behaviour and texture evolution during uniaxial compression of Zircaloy-4 at different temperatures (25, 300, 500 C) has been studied. At room temperature and 300 C the texture evolution and strain-hardening behaviour observed are attributed to the activation of {10-12} tensile twinning, which can be identified in optical micrographs and electron backscatter diffraction (EBSD) data. The influence of twinning upon the texture evolution and hardening rate becomes less apparent with increasing temperature. Nevertheless twinning is still active at 500 C. Simulation of the texture evolution at 500 C using crystal plasticity finite element modelling (CPFEM) indicates that slip alone cannot explain the experimentally observed textures at this temperature.

Microstructural Analysis of Biomedical Co-Cr-Mo Alloy Subjected to High-Pressure Torsion Processing

2014 ◽  
Vol 616 ◽  
pp. 263-269
Author(s):  
Murat Isik ◽  
Mitsuo Niinomi ◽  
Ken Cho ◽  
Masaaki Nakai ◽  
Junko Hieda ◽  
...  
Keyword(s):  
High Pressure ◽  
Vickers Hardness ◽  
High Strain ◽  
High Pressure Torsion ◽  
Electron Backscatter Diffraction ◽  
Microstructural Analysis ◽  
Equivalent Strain ◽  
Ε Phase ◽  
Backscatter Diffraction ◽  
Equiaxed Grains

The effect of high-pressure torsion (HPT) processing on the microstructure and Vickers hardness of Co-Cr-Mo (CCM) alloys were investigated in this study. The microstructure of initial CCM alloy contains equiaxed grains with a grain diameter of approximately 50 μm and twins. The clear grain boundaries of equiaxed grains and twins disappear after HPT processing at a rotation number, N, of 10. The phase maps of initial CCM alloy and CCM alloy subjected to HPT processing at N = 5 measured by electron backscatter diffraction exhibit that the ratio of γ phase decreases from 93.5% to 34.1% and the ratio of ε phase increases from 6.5% to 65.9% by applying HPT processing. These results indicate that the ε phase is formed by high-strain, which is induced by the HPT processing. The Vickers hardness values on the surfaces of the CCM alloys subjected to HPT processing at N = 1, 5, and 10 increase with increasing the equivalent strain, εeq. These results suggest that an increase of Vickers hardness is correlated to an increase of the ratio of ε phase and the dislocation density, and grain refinement, which are caused by the high-strain induced by HPT processing.

scholarly journals Is the Ne operation of the helium ion microscope suitable for electron backscatter diffraction sample preparation?

2021 ◽  
Vol 12 ◽  
pp. 965-983
Author(s):  
Annalena Wolff
Keyword(s):  
Crystal Structure ◽  
Steady State ◽  
Electron Backscatter Diffraction ◽  
Sample Surface ◽  
High Energy ◽  
State Condition ◽  
Steady State Condition ◽  
Helium Ion ◽  
Electron Backscatter ◽  
Backscatter Diffraction

Electron backscatter diffraction (EBSD) is a powerful characterization technique which allows the study of microstructure, grain size, and orientation as well as strain of a crystallographic sample. In addition, the technique can be used for phase analysis. A mirror-flat sample surface is required for this analysis technique and different polishing approaches have been used over the years. A commonly used approach is the focused ion beam (FIB) polishing. Unfortunately, artefacts that can be easily induced by Ga FIB polishing approaches are seldom published. This work aims to provide a better understanding of the underlying causes for artefact formation and to assess if the helium ion microscope is better suited to achieve the required mirror-flat sample surface when operating the ion source with Ne instead of He. Copper was chosen as a test material and polished using Ga and Ne ions with different ion energies as well as incident angles. The results show that crystal structure alterations and, in some instances, phase transformation of Cu to Cu3Ga occurred when polishing with Ga ions. Polishing with high-energy Ne ions at a glancing angle maintains the crystal structure and significantly improves indexing in EBSD measurements. By milling down to a depth equaling the depth of the interaction volume, a steady-state condition of ion impurity concentration and number of induced defects is reached. The EBSD measurements and Monte Carlo simulations indicate that when this steady-state condition is reached more quickly, which can be achieved using high-energy Ne ions at a glancing incidence, then the overall damage to the specimen is reduced.

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