scholarly journals In-Situ Synchrotron Profile Analysis after High-Pressure Torsion Deformation

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 232 ◽  
Author(s):  
Michael Kerber ◽  
Florian Spieckermann ◽  
Roman Schuster ◽  
Bertalan Joni ◽  
Norbert Schell ◽  
...  
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Pressure Torsion ◽  
Profile Analysis ◽  
Heating Process ◽  
Line Profile Analysis ◽  
X Ray ◽  
Pressure Release ◽  
Induced Defects

The presence of hydrostatic pressure is a general crucial characteristic of severe plastic deformation methods for reaching high strains and for introducing large quantities of lattice defects, which are necessary to establish new grain boundaries. Insights into the processes occurring during deformation and the influence of hydrostatic pressure are necessary to help better understand the SPD methods. A special experimental procedure was designed to simulate the hydrostatic pressure release: High pressure torsion (HPT)-deformed microstructure changes related to the release of hydrostatic pressure after the HPT deformation of copper and nickel were studied by freezing the sample before releasing the pressure. High-resolution in-situ X-ray diffraction of the heating process was performed using synchrotron radiation in order to apply X-ray line profile analysis to analyze the pressure release. The results on copper and nickel generally indicated the influence of hydrostatic pressure on the mobility and interaction of deformation-induced defects as well as the resulting microstructure.

Effect of Hydrostatic Pressure on the Microstructure and Mechanical Properties during and after High Pressure Torsion

2010 ◽  
Vol 667-669 ◽  
pp. 657-664 ◽  
Author(s):  
Erhard Schafler
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Pressure Torsion ◽  
Profile Analysis ◽  
Hardness Measurement ◽  
Relaxation Processes ◽  
Line Profile Analysis ◽  
Subgrain Structure ◽  
Pressure Release

The presence of a hydrostatic pressure as a general feature of SPD methods is essential for achieving the high strains and the introduction of the high amount of lattice defects, which are necessary to establish new grain boundaries. Systematic investigations of High Pressure Torsion (HPT)-deformed Cu under variation of strain and hydrostatic pressure revealed marked differences between the in-situ torsional stress (torque measurement) and the post-HPT strength of the ultrafine-grained materials. These facts let assume the occurrence of relaxation processes (recovery/recrystallisation) of static character with respect to the release of the hydrostatic pressure after straining. In order to gain insight into the processes behind, a special experimental procedure was designed to simulate the hydrostatic pressure release. Investigations by X-ray line profile analysis and hardness measurement show marked influences of the pressure release on microstructure and strength. While the size of the coherently scattering domains is not strongly affected, the dislocation density decreases drastically and the arrangement of the dislocations within the subgrain structure changes to a less stress intensive one, upon the pressure release. In parallel the hardness decreases significantly and confirms the discrepancy between in-situ torque-stress and post-HPT strength.

In Situ X-Ray Synchrotron Profile Analysis During High Pressure Torsion of Ti

2017 ◽  
pp. 645-651
Author(s):  
Erhard Schafler ◽  
Michael B. Kerber ◽  
Florian Spieckermann ◽  
Torben Fischer ◽  
Roman Schuster ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Profile Analysis ◽  
X Ray

scholarly journals In situ synchrotron X-ray diffraction line-profile analysis of additively manufactured Ti−6Al−4V alloy under tensile deformation

2020 ◽  
Vol 321 ◽  
pp. 03026
Author(s):  
K. Yamanaka ◽  
A. Kuroda ◽  
M. Ito ◽  
M. Mori ◽  
T. Shobu ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Line Profile ◽  
Tensile Deformation ◽  
Profile Analysis ◽  
High Energy ◽  
Line Profile Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase

In this study, the tensile deformation behavior of an electron beam melted Ti−6Al−4V alloy was examined by in situ X-ray diffraction (XRD) line-profile analysis. The as-built Ti−6Al−4V alloy specimen showed a fine acicular microstructure that was produced through the decomposition of the α′-martensite during the post-melt exposure to high temperatures. Using high-energy synchrotron radiation, XRD line-profile analysis was successfully applied for examining the evolution of dislocation structures not only in the α-matrix but also in the nanosized, low-fraction β-phase precipitates located at the interfaces between the α-laths. The results indicated that the dislocation density was initially higher in the β-phase and an increased dislocation density with increasing applied tensile strain was quantitatively captured in each constitutive phase. It can be thus concluded that the EBM Ti−6Al−4V alloy undergoes a cooperative plastic deformation between the constituent phases in the duplex microstructure. These results also suggested that XRD line-profile analysis combined with highenergy synchrotron XRD measurements can be utilized as a powerful tool for characterizing duplex microstructures in titanium alloys.

Evaluation of X-ray Bragg peak profiles with the variance method obtained by in situ measurement on Mg–Al alloys

2020 ◽  
Vol 53 (2) ◽  
pp. 360-368
Author(s):  
Gergely Farkas ◽  
István Groma ◽  
Jozef Veselý ◽  
Kristián Máthis
Keyword(s):  
Dislocation Density ◽  
Profile Analysis ◽  
Line Profile Analysis ◽  
Dislocation Interaction ◽  
X Ray ◽  
Variance Method ◽  
Al Content ◽  
Transmission Electron ◽  
Bragg Peak Profiles

The microstructural evolution in randomly oriented Mg–Al samples is investigated in situ during compression by X-ray diffraction as a function of Al concentration. The diffraction data are evaluated by the variance method, which provides information about the dislocation density and spatial distribution of the dislocations. The dislocation density increases with increasing alloying content. Since the increment of the dislocation density above the yield point is linear, the mutual dislocation interaction type is determined from the Taylor equation. The results indicate the dominance of basal–basal dislocation interactions, but at higher alloying content the share of the basal–non-basal interactions increases. It is shown that the dynamics of dislocation wall formation also depend on Al content. Transmission electron microscopy observations are in agreement with the results obtained by X-ray line profile analysis.

Texture Evolution of Magnesium Single Crystals Deformed by High-Pressure Torsion

2008 ◽  
Vol 584-586 ◽  
pp. 263-268 ◽  
Author(s):  
Bartlomiej J. Bonarski ◽  
Erhard Schafler ◽  
Borys Mikułowski ◽  
Michael Zehetbauer
Keyword(s):  
High Pressure ◽  
Single Crystals ◽  
Room Temperature ◽  
High Pressure Torsion ◽  
Texture Evolution ◽  
In Situ Stress ◽  
Higher Symmetry ◽  
Strain Measurements ◽  
X Ray

Single crystals of technical purity Magnesium (99.8 wt.%) of initial orientations [ ] 2 1 10 and [ ] 2 2 11 were subjected to HPT deformation at room temperature up to strains of 10. The microstructural evolution has been analyzed by X-ray microtexture investigations and by in-situ stress-strain measurements. The results can be described in terms of shear arising from HPT deformation and - with higher strains - in terms of recrystallization. In crystals with hard orientation[ ] 2 2 11 , these features occur at smaller strains than in crystals with soft orientation [ ] 2 1 10 , i.e. with higher symmetry. In general, the observed textures and strength variations are much stronger than those reported for fcc HPT deformed metals.

Nanocrystallization and Dissolution of Immiscible Powder Alloys Using High Pressure Torsion

2010 ◽  
Vol 667-669 ◽  
pp. 151-156
Author(s):  
Susi Kahofer ◽  
Michael Zehetbauer ◽  
Herbert Danninger ◽  
Erhard Schafler ◽  
Michael Kerber ◽  
...  
Keyword(s):  
Room Temperature ◽  
Vickers Microhardness ◽  
High Pressure Torsion ◽  
Profile Analysis ◽  
Line Profile Analysis ◽  
X Ray ◽  
Grain Sizes ◽  
Powder Alloys ◽  
Microhardness Data ◽  
Different Strains

Precompacts out of immiscible systems CuCr (75/25 wt%) and WCu (80/20 wt%), respectively, were made by pressing mixed powders and sintering. By applying different strains and hydrostatic pressures of HPT at room temperature, disc-shaped samples with a diameter of 8 mm were produced. They were investigated by Light Microscopy, Scanning-Electron Microscopy using Back-Scattered Electrons, and X-ray Line Profile Analysis. In addition, Vickers microhardness data were collected. Both systems showed the highest microhardness at a shear strain of about γ = 170. The density (for the case of Cu25Cr) of the consolidated material could be increased to the theoretical value. Microhardness and grain sizes were studied individually for each of the phases, too.

The Role of Interfaces in Evolution of Structure and Thermal Stability of Cu-Nb Composite Processed by High-Pressure Torsion

2018 ◽  
Vol 383 ◽  
pp. 118-124 ◽  
Author(s):  
E.N. Popova ◽  
I.L. Deryagina ◽  
E.G. Valova-Zaharevskaya ◽  
Alexey V. Stolbovsky
Keyword(s):  
Thermal Stability ◽  
High Pressure ◽  
High Pressure Torsion ◽  
Cold Drawing ◽  
X Ray ◽  
Evolution Of Structure ◽  
Equiaxed Grains ◽  
Thermal Stability Of

The structure and thermal stability of Cu-18Nb multicore composite fabricated by repeated cold-drawing of in situ melted mixture of Cu and Nb and subjected to high-pressure torsion (HPT) have been studied by SEM, TEM, X-ray analysis and microhardness measurements. In the cold-drawn state ribbon-like Nb filaments the thickness of 30-70 nm are located in Cu-matrix with sharp texture <110>Nb║<111>Cu║drawing axis. The Nb lattice is distorted, the interplanar spacing (110)Nb being extended along the drawing axis and compressed perpendicular to it, which testifies a semi-coherent character of Cu/Nb interfaces. At annealing these distorsions gradually vanish, and coagulation of Nb ribbons starts at 400С, actively develops at 600С and finishes at 800С with the formation of sausage-like filaments with round transverse sections, which is accompanied with about two-fold decreasing of microhardness. Under the HPT the composite structure is considerably refined, and almost equiaxed grains the sizes of 20-30 nm are formed, which gives rise to a dramatic increase of microhardness. The thermal stability of Cu-Nb composite after cold drawing and HPT is appreciably higher than that of pure Nb and Cu nanostructured by severe plastic deformation.

X-ray reflectivity measurements of liquid/solid interfaces under high hydrostatic pressure conditions

2013 ◽  
Vol 21 (1) ◽  
pp. 76-81 ◽  
Author(s):  
Florian J. Wirkert ◽  
Michael Paulus ◽  
Julia Nase ◽  
Johannes Möller ◽  
Simon Kujawski ◽  
...  
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Protein Unfolding ◽  
High Pressure Cell ◽  
X Ray ◽  
Pressure Cell ◽  
Set Up ◽  
Pressure Regime

A high-pressure cell forin situX-ray reflectivity measurements of liquid/solid interfaces at hydrostatic pressures up to 500 MPa (5 kbar), a pressure regime that is particularly important for the study of protein unfolding, is presented. The original set-up of this hydrostatic high-pressure cell is discussed and its unique properties are demonstrated by the investigation of pressure-induced adsorption of the protein lysozyme onto hydrophobic silicon wafers. The presented results emphasize the enormous potential of X-ray reflectivity studies under high hydrostatic pressure conditions for thein situinvestigation of adsorption phenomena in biological systems.

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