High pressure deformation study of zirconium

2007 ◽  
Vol 22 (2) ◽  
pp. 113-117 ◽  
Author(s):  
Sven C. Vogel ◽  
Helmut Reiche ◽  
Donald W. Brown
Keyword(s):  
Plastic Deformation ◽  
Hydrostatic Pressure ◽  
High Pressures ◽  
Texture Evolution ◽  
Compressive Load ◽  
Vertical Direction ◽  
Tensile Load ◽  
Polycrystalline Materials ◽  
Active Deformation ◽  
Elastic And Plastic Deformation

In situ deformation studies of polycrystalline materials using diffraction are an established method to understand elastic and plastic deformation of materials. Studies of active deformation mechanisms, the interplay of deformation with texture, and ultimately the development of predictive capabilities for deformation modeling are an active field of research. Parameters studied by diffraction are typically lattice strains and texture evolution, which coupled with the macroscopic flow curve allow for improved understanding of the micro-mechanics of deformation. We performed a study of the uniaxial deformation of Zircaloy-2 at 2 GPa at the 13-BM-D beamline at the Advanced Photon Source. The deformation-DIA apparatus generates a confining hydrostatic pressure using a cubic anvil setup. Two differential rams allow an increase (compressive load) or decrease (tensile load) of the uniaxial straining in the vertical direction, allowing studies of plastic deformation at high pressures. In this paper, we describe how macroscopic strains, hydrostatic pressure, and uniaxial strains are derived and present some brief results.

Application of the 3D X-Ray Crystal Microscope to Study Mesoscale Structure of Materials

2003 ◽  
Vol 779 ◽  
Author(s):  
Gene E. Ice ◽  
Wenjun Liu ◽  
Bennett C. Larson ◽  
Fredrick J. Walker
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Three Dimensions ◽  
Polycrystalline Materials ◽  
Crystalline Orientation ◽  
Materials Properties ◽  
X Ray ◽  
Mesoscale Structure ◽  
Elastic And Plastic Deformation ◽  
Strain Tensors

AbstractThe 3D x-ray crystal microscope is an emerging tool for the study of mesoscale structure in polycrystalline materials. With this nondestructive device, local crystalline orientation, phase, elastic and plastic strain tensors can be measured with submicron spatial resolution in three dimensions. A key step in analyzing the Laue patterns from the 3D microscope is indexing the reflections, which determines the orientation of the sub-grain. With current algorithms, the angles between pairs, triplets and quadruplets of reflections are compared to theoretical angles to make guesses as to the reflection indices. The ability to index a pattern can however be compromised by both elastic and plastic deformation of a grain; elastic deformation changes the angles between reflections and plastic deformation increases the uncertainty in the centroid of each reflection. Here we report on the use of an indexing algorithm that simultaneously fits all peaks from a subgrain. This algorithm is more robust than previous methods and allows for indexing of deformed or strained grains. Some applications to studies of mesoscale materials properties are described.

scholarly journals Polycrystal Simulation of Texture-Induced Grain Coarsening during Severe Plastic Deformation

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5834
Author(s):  
Chi Zhang ◽  
Laszlo S. Toth
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Electron Backscatter Diffraction ◽  
Texture Evolution ◽  
Face Centered Cubic ◽  
Shear Texture ◽  
Grain Coarsening ◽  
Random Texture ◽  
Polycrystal Plasticity ◽  
Grain Fragmentation

During severe plastic deformation (SPD), there is usually extended grain fragmentation, associated with the formation of a crystallographic texture. The effect of texture evolution is, however, coarsening in grain size, as neighbor grains might coalesce into one grain by approaching the same ideal orientation. This work investigates the texture-induced grain coarsening effect in face-centered cubic polycrystals during simple shear, in 3D topology. The 3D polycrystal aggregate was constructed using a cellular automaton model with periodic boundary conditions. The grains constituting the polycrystal were assigned to orientations, which were updated using the Taylor polycrystal plasticity approach. At the end of plastic straining, a grain detection procedure (similar to the one in electron backscatter diffraction, but in 3D) was applied to detect if the orientation difference between neighboring grains decreased below a small critical value (5°). Three types of initial textures were considered in the simulations: shear texture, random texture, and cube-type texture. The most affected case was the further shearing of an initially already shear texture: nearly 40% of the initial volume was concerned by the coalescence effect at a shear strain of 4. The coarsening was less in the initial random texture (~30%) and the smallest in the cube-type texture (~20%). The number of neighboring grains coalescing into one grain went up to 12. It is concluded that the texture-induced coarsening effect in SPD processing cannot be ignored and should be taken into account in the grain fragmentation process.

Microstructure and Texture Evolution in a Cold-Rolled High Mn Steel with Microadditions of Ti and Nb

2013 ◽  
Vol 203-204 ◽  
pp. 71-76
Author(s):  
Sławomir Kołodziej ◽  
Joanna Kowalska ◽  
Wiktoria Ratuszek ◽  
Wojciech Ozgowicz ◽  
Krzysztof Chruściel
Keyword(s):  
Plastic Deformation ◽  
Texture Evolution ◽  
Hexagonal Structure ◽  
Cold Plastic Deformation ◽  
Α Phase ◽  
Ε Phase ◽  
Cold Rolled ◽  
Goss Orientation ◽  
Mn Steel ◽  
Microscopic Investigations

The aim of this work was the microstructure and texture analysis of a deformed via cold-rolling 24.5Mn-3.5Si-1.5Al-Ti-Nb TWIP/TRIP type steel. It was found, that during cold plastic deformation a phase transformation of austenite into martensite takes place. The transformation progress was confirmed by the microscopic investigations. The texture of austenite is characterized by a limited α1=||RD fibre and the γ=||ND fibre. The texture of austenite changed with increasing deformation rate. In the texture of deformed austenite the strongest orientation is the {110} Goss orientation, which belongs to the α=||ND orientation fibre. During cold plastic deformation γ→ε and γ→ε→α’ phase transformations as well as the deformation of γ, ε and α’ phases are taking place in the steel. The formed ε phase (hexagonal structure) also possesses a distinct texture.

Stages of plastic deformation of polycrystalline materials

2017 ◽  
pp. 1-49 ◽  
Author(s):  
A. M. Glezer ◽  
E. V. Kozlov ◽  
N. A. Koneva ◽  
N. A. Popova ◽  
I. A. Kurzina
Keyword(s):  
Plastic Deformation ◽  
Polycrystalline Materials

scholarly journals Strength of Bonds between Ice Grains after Short Contact Times

1982 ◽  
Vol 28 (100) ◽  
pp. 457-473 ◽  
Author(s):  
H. Gubler
Keyword(s):  
Plastic Deformation ◽  
Sharp Increase ◽  
Maximum Rate ◽  
Load Capacity ◽  
Tensile Force ◽  
Tensile Load ◽  
Surface Flow ◽  
Initial State ◽  
Short Contact ◽  
Rate Of Increase

AbstractThe tensile force required to break bonds between ice grains after short contact times (1–500 s) is measured as a function of temperature and contact pressure. The results indicate a sharp increase of the tensile load capacity of bonds alter short contact times near the melting point and a maximum rate of increase of the load capacity at −5 °C. The initial state or sintering is modelled, assuming viscous surface flow and plastic deformation as the main mechanisms.

Uplift behaviour of tapered piles established from model tests

2000 ◽  
Vol 37 (1) ◽  
pp. 56-74 ◽  
Author(s):  
M Hesham El Naggar ◽  
Jin Qi Wei
Keyword(s):  
Load Transfer ◽  
Compressive Loading ◽  
Compressive Load ◽  
Tensile Load ◽  
Confining Pressure ◽  
Cohesionless Soil ◽  
Uplift Capacity ◽  
Experimental Modelling ◽  
Confining Pressures ◽  
Load Tests

Tapered piles have a substantial advantage with regard to their load-carrying capacity in the downward frictional mode. The uplift performance of tapered piles, however, has not been fully understood. This paper describes the results of an experimental investigation into the characteristics of the uplift performance of tapered piles. Three instrumented steel piles with different degrees of taper were installed in cohesionless soil and subjected to compressive and tensile load tests. The soil was contained in a steel soil chamber and pressurized using an air bladder to facilitate modelling the confining pressures pertinent to larger embedment depths. The results of this study indicated that the pile axial uplift capacity increased with an increase in the confining pressure for all piles examined in this study. The ratios of uplift to compressive load for tapered piles were less than those for straight piles of the same length and average embedded diameter. The uplift capacity of tapered piles was found to be comparable to that of straight-sided wall piles at higher confining pressure values, suggesting that the performance of actual tapered piles (with greater length) would be comparable to that of straight-sided wall piles. Also, the results indicated that residual stresses developed during the compressive loading phase and their effect were more significant on the initial uplift capacity of piles, and this effect was more pronounced for tapered piles in medium-dense sand.Key words: tapered piles, uplift, axial response, load transfer, experimental modelling.

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