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.

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.

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.

HPT-Deformation of Copper and Nickel Single Crystals

2006 ◽  
Vol 503-504 ◽  
pp. 621-626 ◽  
Author(s):  
Martin Hafok ◽  
A. Vorhauer ◽  
Jozef Keckes ◽  
Reinhard Pippan
Keyword(s):  
Single Crystals ◽  
High Pressure Torsion ◽  
Electron Backscatter Diffraction ◽  
Structural Evolution ◽  
Equivalent Strain ◽  
Textural Evolution ◽  
Dynamical Recovery ◽  
Backscatter Diffraction ◽  
Plastic Equivalent Strain ◽  
Formed Structure

Copper and nickel single crystals of high purity with a crystallographic orientation, (001) and (111) respectively, were deformed by applying high pressure torsion (HPT) at room temperature. Special interest was devoted to the structural evolution of the material, which was characterized by electron backscatter diffraction (EBSD) and X-ray texture analysis as well. In addition back scatter electron investigations were applied to characterize shape and size of the new formed structure. Furthermore the study is focused on the micro structural and micro textural evolution that lead to the increase of missorientation angle with increasing plastic deformation. We observed an increasing fragmentation of the structure with increasing plastic equivalent strain up to a level where the grain size is saturated. The saturation could be traced back to dynamical recovery and recrystallisation during the deformation process that is depending on the purity of the material.

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.

Deformation-Induced Solid-State Amorphization in a Nanostructured Al-Mg Alloy Processed by High Pressure Torsion

2015 ◽  
Vol 817 ◽  
pp. 627-633 ◽  
Author(s):  
Man Ping Liu ◽  
Xue Feng Xie ◽  
Zhen Ya Zhang ◽  
Hui Wang ◽  
Hans J. Roven
Keyword(s):  
High Pressure ◽  
Solid State ◽  
High Pressure Torsion ◽  
Electron Backscatter Diffraction ◽  
Mg Alloy ◽  
Strong Interactions ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Backscatter Diffraction ◽  
State Amorphization

This work reports the experimental evidence of localized solid-state amorphization (SSA) in a nanostructured Al–Mg alloy processed by high pressure torsion at room temperature. Electron backscatter diffraction analysis indicated that the deformed alloy had a very small average grain size of about 79 nm. High-resolution transmission electron microscopy (HRTEM) observations illustrated that the deformation-induced SSA were frequently located in the vicinity of grain boundaries (GBs) and GB junctions where high density dislocations, severe lattice distortion, deformation twins and stacking faults coexisted in the deformed alloy. The SSA phenomenon may primarily be attributed to the strong interactions of the high dislocation densities, GBs and the planar interfaces. A possible formation process of amorphization is proposed based on the HRTEM investigations. The present results suggest that the crystalline-to-amorphous transformation could also occur in binary Al–Mg alloys through severe plastic deformation that are usually produced by rapid solidification.

Analysis and characterization by electron backscatter diffraction of microstructural evolution in the adiabatic shear bands in Fe–Cr–Ni alloys

2009 ◽  
Vol 24 (8) ◽  
pp. 2617-2627 ◽  
Author(s):  
Huajie Yang ◽  
Yongbo Xu ◽  
Yasuaki Seki ◽  
Vitali F. Nesterenko ◽  
Marc André Meyers
Keyword(s):  
Microstructural Evolution ◽  
Electron Backscatter Diffraction ◽  
Shear Bands ◽  
Adiabatic Shear ◽  
Adiabatic Shear Bands ◽  
Localized Deformation ◽  
Ni Alloys ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Equiaxed Grains

The microstructural evolution inside adiabatic shear bands in Fe–Cr–Ni alloys dynamically deformed (strain rates > 104 s−1) by the collapse of an explosively driven, thick-walled cylinder under prescribed strain conditions was examined by electron backscatter diffraction. The observed structure within the bands consisted of both equiaxed and elongated grains with a size of ∼200 nm. These fine microstructures can be attributed to recrystallization; it is proposed that the elongated grains may be developed simultaneously with localized deformation (dynamic recrystallization), and the equiaxed grains may be formed subsequently to deformation (static recrystallization). These recrystallized structures can be explained by a rotational recrystallization mechanism.

Microstructure and Microhardness of Copper Subjected to High Pressure Torsion

2011 ◽  
Vol 194-196 ◽  
pp. 712-715 ◽  
Author(s):  
Zi Ling Xie ◽  
Lin Zhu Sun ◽  
Fang Yang ◽  
Xiao Bing Li
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Type Equation ◽  
Longitudinal Section ◽  
Dislocation Cell ◽  
Subgrain Structure ◽  
Structure Morphology ◽  
Evolution Of Microstructure ◽  
Equiaxed Grains ◽  
Variation Tendency

Experiments were conducted on copper subjected to High Pressure Torsion to investigate the evolution of microstructure and microhardness with shear strain, γ. Observations have been carried out in the longitudinal section for a proper demonstration of the structure morphology. An elongated dislocation cell/subgrain structure was observed at relatively low strain level. With increasing strain, the elongated subgrains transformed into elongated grains and finally into equiaxed grains with high angle grain boundaries. Measurements showed the hardness increases with increasing γ then tends to saturations when γ >5. The variation tendency of microhardness with γ can be simulated by Voce-type equation.

scholarly journals Microstructural constraints on magmatic mushes under Kīlauea Volcano, Hawaiʻi

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Penny E. Wieser ◽  
Marie Edmonds ◽  
John Maclennan ◽  
John Wheeler
Keyword(s):  
Spatial Distribution ◽  
Dendritic Growth ◽  
Electron Backscatter Diffraction ◽  
Microstructural Analysis ◽  
Kilauea Volcano ◽  
Kīlauea Volcano ◽  
Mantle Peridotites ◽  
Wide Range ◽  
Electron Backscatter ◽  
Backscatter Diffraction

AbstractDistorted olivines of enigmatic origin are ubiquitous in erupted products from a wide range of volcanic systems (e.g., Hawaiʻi, Iceland, Andes). Investigation of these features at Kīlauea Volcano, Hawaiʻi, using an integrative crystallographic and chemical approach places quantitative constraints on mush pile thicknesses. Electron backscatter diffraction (EBSD) reveals that the microstructural features of distorted olivines, whose chemical composition is distinct from undistorted olivines, are remarkably similar to olivines within deformed mantle peridotites, but inconsistent with an origin from dendritic growth. This, alongside the spatial distribution of distorted grains and the absence of adcumulate textures, suggests that olivines were deformed within melt-rich mush piles accumulating within the summit reservoir. Quantitative analysis of subgrain geometry reveals that olivines experienced differential stresses of ∼3–12 MPa, consistent with their storage in mush piles with thicknesses of a few hundred metres. Overall, our microstructural analysis of erupted crystals provides novel insights into mush-rich magmatic systems.

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