scholarly journals Twin induced Strain Hardening, Grain Fragmentation, and Texture Evolution during Cold Compression of CP-Ti

2021 ◽  
Vol 1121 (1) ◽  
pp. 012026
Author(s):  
Devesh Kumar Chouhan ◽  
Somjeet Biswas
Keyword(s):  
Strain Hardening ◽  
Texture Evolution ◽  
Cold Compression ◽  
Grain Fragmentation ◽  
Cp Ti

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.

On the Relationship between Pseudoelasticity and Texture Evolution in Ti-26Nb-0.5Si Alloy

2007 ◽  
Vol 558-559 ◽  
pp. 1407-1411
Author(s):  
Won Yong Kim ◽  
Han Sol Kim
Keyword(s):  
Strain Hardening ◽  
Volume Fraction ◽  
Texture Evolution ◽  
Flow Behavior ◽  
High Stress ◽  
Two Stage ◽  
Β Phase ◽  
Three Phase ◽  
The Relationship ◽  
Strain Hardening Rate

Texture and cyclic tensile behavior of Ti-26Nb-0.5Si (denoted as atomic percent) alloys in which the microstructures were varied by quenching, cold rolling and recrystallization heat treatment were investigated in order to understand the relationship between pseudoelastic behavior and texture formation. Three phase mixtures consisting of bcc-structured β phase, orthorhombic structured α" phase and hcp-structured intermediate ω phase were characterized to display the constituent phases. The volume fraction of constituent phases was found to be insensitive to the given materials processing. Two-stage yielding, one at low stress with low strain hardening rate and the other one at high stress with high strain hardening rate, appeared to exhibit a characteristic flow behavior in the present alloys. It is revealed that stress-induced martensite transformation resulting in two-stage yielding was closely associated with pseudoelasticity. On the basis of texture analyses, we have suggested that pseudoelasticity of the present alloys is hindered by the development of {001}<110> rotated cube component.

Deformation twinning in rolled WE43-T5 rare earth magnesium alloy: Influence on strain hardening and texture evolution

2017 ◽  
Vol 131 ◽  
pp. 221-232 ◽  
Author(s):  
Mohammad Jahedi ◽  
Brandon A. McWilliams ◽  
Paul Moy ◽  
Marko Knezevic
Keyword(s):  
Rare Earth ◽  
Magnesium Alloy ◽  
Strain Hardening ◽  
Texture Evolution ◽  
Deformation Twinning

Deformation twinning in AZ31: Influence on strain hardening and texture evolution

2010 ◽  
Vol 58 (19) ◽  
pp. 6230-6242 ◽  
Author(s):  
Marko Knezevic ◽  
Amanda Levinson ◽  
Ryan Harris ◽  
Raja K. Mishra ◽  
Roger D. Doherty ◽  
...  
Keyword(s):  
Strain Hardening ◽  
Texture Evolution ◽  
Deformation Twinning

scholarly journals Influence of Yttrium Addition on Texture and Deformation Behavior in an Extruded ZM31 Alloy

2021 ◽  
Author(s):  
Nabila Tahreen
Keyword(s):  
Strain Hardening ◽  
Magnesium Alloys ◽  
Deformation Behavior ◽  
Business Models ◽  
Mechanical Response ◽  
Texture Evolution ◽  
Strain Curve ◽  
True Stress ◽  
Dislocation Slip ◽  
Microstructural Development

The current “storm” of lightweighting, a revolution in materials, processes, and business models, which is brewing on the horizon of the auto industry, inspires researchers and engineers to develop and apply new wrought magnesium alloys with improved properties. For wider applications in the automotive and aerospace industries, the enhancement of strength, thermal stability and formability of magnesium alloys is required. In recent years, Mg-Zn-Y series alloys have received a considerable attention from the research community due to their improved mechanical properties. The present study was aimed at evaluating the influence of Y addition to Mg-Zn-Mn system based on phase formation, mechanical response and texture development with special attention paid to recrystallization, hot characterization and relative activity. The dissertation evaluated the strain hardening and deformation behavior of as-extruded Mg-ZnMn (ZM31) magnesium alloy with varying Y contents via compression testing at room temperature, 200°C and 300°C. Alloy ZM31+0.3Y consisted I-phase (Mg3YZn6); alloy ZM31+3.2Y contained I-phase and W-phase (Mg3Y2Zn3); alloy ZM31+6Y had long-period stacking-ordered (LPSO) X-phase (Mg12YZn) and Mg24Y5 particles. With increasing Y content the basal texture became weakened significantly. While alloys ZM31+0.3Y and ZM31+3.2Y exhibited a skewed true stress-true stain curve with a three-stage strain hardening feature caused by the occurrence of {10 Ī 2} extension twinning, the true stress-true strain curve of alloy ZM31+6Y was normal due to the dislocation slip during compression. The evolution of flow stress, texture and microstructure during the compression tests has been studied under various conditions of temperature and strain rates. Optical metallography, EBSD techniques and X-ray diffraction were employed to study the microstructural development and texture evolution. The deformation activation energy was calculated and the processing maps were generated to determine the optimum hot working parameters. In addition, viscoplastic selfconsistent model was successfully used to predict the experimental textures. Lastly, the strengthening mechanisms in each Mg-Zn-Mn-Y material are established quantitatively for the first time to account for grain refinement, thermal mismatch, dislocation density, load bearing, and particle strengthening contributions. The present work laid the foundations for a better understanding the role of Y elements on deformation behavior in magnesium alloys.

scholarly journals Experimental and Numerical Study of Texture Evolution and Anisotropic Plastic Deformation of Pure Magnesium under Various Strain Paths

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Hamad F. Alharbi ◽  
Monis Luqman ◽  
Ehab El-Danaf ◽  
Nabeel H. Alharthi
Keyword(s):  
Strain Hardening ◽  
Uniaxial Tension ◽  
Plane Strain ◽  
Texture Evolution ◽  
Plane Strain Compression ◽  
Pure Magnesium ◽  
Deformation Mechanisms ◽  
Slip Systems ◽  
Simple Compression ◽  
Strain Paths

The deformation behavior and texture evolution of pure magnesium were investigated during plane strain compression, simple compression, and uniaxial tension at room temperature. The distinctive stages in the measured anisotropic stress-strain responses and numerically computed strain-hardening rates were correlated with texture and deformation mechanisms. More specifically, in plane strain compression and simple compression, the onset of tensile twins and the accompanying texture-hardening effect were associated with the initial high strain-hardening rates observed in specimens loaded in directions perpendicular to the crystallographic c-axis in most of the grains. The subsequent drop in strain-hardening rates in these samples was correlated with the exhaustion of tensile twins and the activation of pyramidal <c+a> slip systems. The falling strain-hardening rates were observed in simple compression and plane strain compression with loading directions parallel to the c-axis where the second pyramidal <c+a> slip systems were the only slip families that can accommodate deformation. For uniaxial tension with the basal plane parallel to the tensile axis, the prismatic <a> and second pyramidal <c+a> slips are the main deformation mechanisms. The predicted relative slip and twin activities from the crystal plasticity simulations clearly showed the effect of texture on the type of activated deformation mechanisms.

Evaluation of Press Formability of Pure Titanium Sheets

2016 ◽  
Vol 716 ◽  
pp. 87-98 ◽  
Author(s):  
Quoc Tuan Pham ◽  
Young Suk Kim
Keyword(s):  
Strain Hardening ◽  
Pure Titanium ◽  
Yield Function ◽  
Forming Limit ◽  
Commercially Pure Titanium ◽  
Specific Strength ◽  
Force Criterion ◽  
Stress Strain Relation ◽  
Cp Ti ◽  
Press Formability

Commercially pure titanium (CP Ti) has been actively used in plate heat exchangers due to its light weight, high specific strength, and excellent corrosion resistance. However compared with automotive steels and aluminum alloys, only limited research has been conducted on the plastic deformation characteristics and press formability of CP Ti sheets. In this study, the mechanical properties, including the anisotropic property and the stress-strain relation, of the CP Ti sheet are clarified in relation to press formability. A new proposed strain hardening model, Kim-Tuan equation, is successful in perfectly describing the stress evaluation for strain increment of this material during strain path. The forming limit curve (FLC) of the CP Ti sheet as a criterion for press formability was experimentally evaluated by punch stretching testing and analytically predicted via Hora’s modified maximum force criterion. The predicted FLC based on the Kim-Tuan strain hardening equation and the appropriate yield function correlates well with the experimental results of the punch stretching test.

scholarly journals Microstructure and Texture Evolution in a Post-dynamic Recrystallized Titanium During Annealing, Monotonic and Cyclic Loading

2020 ◽  
Vol 52 (1) ◽  
pp. 394-412
Author(s):  
P.-C. Zhao ◽  
B. Chen ◽  
Z.-G. Zheng ◽  
B. Guan ◽  
X.-C. Zhang ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Grain Growth ◽  
Texture Evolution ◽  
Coincidence Site Lattice ◽  
Lattice Rotation ◽  
Dislocation Slip ◽  
Boundary State ◽  
Basal Pole ◽  
Dynamic Recrystallization Behavior ◽  
Cp Ti

Abstract The post-dynamic recrystallization behavior of ultrafine-grained (UFG: 0.44 μm) cp-Ti under annealing, room temperature (RT) monotonic and cyclic loading was investigated across a range of temperatures and deformation rates wherever appropriate. By characterizing the grain and boundary structures, it was confirmed that recrystallization and grain growth occurred due to annealing (≥ 600 °C) and R = − 1 fatigue at RT. There was a noticeable 30 deg aggregation in misorientation distribution, along with the increased grain size. However, the hypothetical correlation between 30 deg aggregation and Σ13a or the other characteristic coincidence site lattice boundaries was found to be weak. The fatigue-induced grain growth is particularly intriguing for two reasons. First, the large monotonic deformation with low strain rate cannot trigger grain growth. Second, fatigue sharpened the basal intensity around the ND and caused a weaker texture component close to TD (load axis along the LD, perpendicular to the TD–ND plane). By contrast, high-temperature annealing only strengthened the UFG processing induced basal pole but without affecting its location. Novel insights into this fatigue-induced texture evolution in UFG cp-Ti has been provided. The lattice rotation during fatigue can be attributed to the combined effect of activation of prismatic $$ \langle a\rangle $$ ⟨ a ⟩ slip parallel to LD, and basal $$ \langle a\rangle $$ ⟨ a ⟩ slip perpendicular to it. The theoretically calculated stress to activate dislocation slip by assuming a non-equilibrium grain boundary state lent support to the above assertion. Moreover, the TEM observation evidently showed the characteristics of dislocation cross-slip and multiple slip in the grain interior. Graphical Abstract

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