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 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.

Application of the VPSC Model to the Description of the Stress–Strain Response and Texture Evolution in AZ31 Mg for Various Strain Paths

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Nitin Chandola ◽  
Raja K. Mishra ◽  
Oana Cazacu
Keyword(s):  
Mechanical Response ◽  
Mechanical Test ◽  
Texture Evolution ◽  
Mean Field ◽  
Strain Curve ◽  
Temperature Deformation ◽  
Strain Response ◽  
Stress Strain ◽  
Self Consistent ◽  
Strain Paths

Accurate description of the mechanical response of AZ31 Mg requires consideration of its strong anisotropy both at the single crystal and polycrystal levels, and its evolution with accumulated plastic deformation. In this paper, a self-consistent mean field crystal plasticity model, viscoplastic self-consistent (VPSC), is used for modeling the room-temperature deformation of AZ31 Mg. A step-by-step procedure to calibrate the material parameters based on simple tensile and compressive mechanical test data is outlined. It is shown that the model predicts with great accuracy both the macroscopic stress–strain response and the evolving texture for these strain paths used for calibration. The stress–strain response and texture evolution for loading paths that were not used for calibration, including off-axis uniaxial loadings and simple shear, are also well described. In particular, VPSC model predicts that for uniaxial tension along the through-thickness direction, the stress–strain curve should have a sigmoidal shape.

Deformation Mechanisms of a Micro-Sized Austenitic Stainless Steel with Fine Grains

2000 ◽  
Vol 657 ◽  
Author(s):  
G. P. Zhang ◽  
K. Takashima ◽  
M. Shimojo ◽  
Y. Higo
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Strain Hardening ◽  
Deformation Behavior ◽  
Testing Machine ◽  
Grain Boundary Sliding ◽  
Deformation Mechanisms ◽  
Dislocation Slip ◽  
Intergranular Cracking ◽  
Micro Cantilever

ABSTRACTIn this study, deformation behavior of fine-grained austenitic stainless steel micro-cantilever beams was investigated using a newly developed testing machine for micro-sized specimens. The microbeams were deformed to different strain hardening stages of the material, and then the detailed deformation behavior on the specimen surface at the corresponding strain hardening stage was examined by scanning electron microscopy. Two deformation mechanisms corresponding to different strain hardening stages were found in the micro-sized austenitic stainless steel with fine grains. The dislocation slip mechanism characterized by the extensive dislocation slips and their interaction with grain boundaries resulted in the stage I strain hardening. With increasing deformation, the grain boundary sliding (GBS) mechanism at the stage II and subsequently intergranular cracking occurred. The differences in stress condition and work-hardening behavior on the top tension-side and rear compression-side surfaces of the micro-cantilever beam resulted in the different deformation behavior.

Studies on Related ms Magnitude Rate Models in Triangular Wave Unloading Section of Calcium Medium-Fine Sandstone

2010 ◽  
Vol 152-153 ◽  
pp. 164-170
Author(s):  
Jie Liu ◽  
Jian Lin Li ◽  
Ying Xia Li ◽  
Shan Shan Yang ◽  
Ji Fang Zhou ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Strain Curve ◽  
Experimental System ◽  
Constant Term ◽  
Lag Time ◽  
Vertical Force ◽  
Time Segment ◽  
Triangular Wave ◽  
Apparent Modulus ◽  
The Impact

Specific to the improvement in the present research of mechanical response under cyclic loading, this paper, taking the calcareous middle- coarse sandstone as the research subject and the RMT-150C experimental system in which data is recoded by ms magnitude as the platform, develops several related models concerning the unloading rate of triangle waves. The unloading process is divided into lag time segment and non-lag time segment, with criterions and related parameters provided as well. The term apparent elastic modulus is defined. The test data analysis shows that there exist a linear relationship between the apparent modulus and instant vertical force before load damage in non-lag time segment. On the preceding basis, a rate-dependent model of triangular wave un-installation section in non-lag time segment is established. Due to the inability of the loading equipment to accurately input the triangle wave, the average loading rate is amended and a constant term is added into it. The model is proved to be reliable, as the predicted value of the deformation rate and the stress strain curve coincides with measured value. At the same time, the impact of the lag time is pointed out quantitatively and a predication model of lag time segment is set up.

Study on Constitutive Modeling for Large Deformation Behavior of Polyethylene Considering Strain Rate Effect

2013 ◽  
Author(s):  
Sijia Zhong ◽  
Jianfeng Shi ◽  
Jinyang Zheng
Keyword(s):  
Strain Rate ◽  
Large Deformation ◽  
Constitutive Modeling ◽  
Deformation Behavior ◽  
True Strain ◽  
True Stress ◽  
Uniaxial Tensile ◽  
Pipeline System ◽  
Composite Effect ◽  
Time Deformation

Polyethylene (PE) pipes have been applied in transportation of key energy medium such as natural gas in the past decades. The mechanical property of PE is of great importance for better design and safer application of PE pipeline system. The large deformation behavior is a key character of PE, not only for its significant strain rate sensitivity, but also for localized necking process after yielding. In this paper, a new constitutive modeling method was proposed to charaterize the rate-denpendent large deformation behavior of PE, in which the true stress is regarded as a function of true stain and true strain rate alone. Uniaxial tensile tests of PE were conducted under various cross-head speeds, and a digital camera was used to record the real-time deformation of specimens. By separating the composite effect into respective effect of local true strain and strain rate on the local true stress in the necking region, a phenomenological model for describing the rate-dependent deformation behavior under uniaxial tension was ealstablished. Model results were validated and found in good agreement with experimental data.

Hot Compression Deformation Behavior of Spray-Formed AlSn20Cu Alloy

2021 ◽  
Vol 1035 ◽  
pp. 189-197
Author(s):  
Bao Ying Li ◽  
Bao Hong Zhu
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Deformation Temperature ◽  
Phase Distribution ◽  
True Stress ◽  
Hot Compression ◽  
Test Machine ◽  
Hot Compression Deformation ◽  
Compression Deformation

The hot deformation behavior of spray-formed AlSn20Cu alloy during hot compression deformation was studied, and the constitutive equation of AlSn20Cu alloy was established. The samples of spray-formed AlSn20Cu alloy were compressed on Gleeble-3500 thermal simulation test machine. The error of the true stress caused by adiabatic heating effect in the experiment was corrected. The constitutive equation of spray-formed AlSn20Cu alloy could be represented by Zener-Hollomon parameter in a hyperbolic sine function. The results showed that the deformation temperatures and strain rates had a notable effect on the true stress of the alloy. At the identical deformation temperature, the true stress increased with the increase of strain rate. When the strain rate was constant, the stress decreased with the increase of deformation temperature. After hot compression deformation, the tin phase was elongated along the direction perpendicular to the compression axis with short strips and blocks. With the increase of deformation temperature and the decrease of strain rate, Sn phase distribution became more homogeneous.

FINITE ELEMENT STUDY OF MULTIPASS EQUAL CHANNEL ANGULAR EXTRUSION/PRESSING

2005 ◽  
Vol 04 (04) ◽  
pp. 745-751 ◽  
Author(s):  
A. V. NAGASEKHAR ◽  
TICK-HON YIP ◽  
S. LI
Keyword(s):  
Finite Element ◽  
Strain Hardening ◽  
Deformation Behavior ◽  
Equal Channel Angular Extrusion ◽  
Finite Element Code ◽  
Hardening Behavior ◽  
Strain Homogeneity ◽  
Angular Extrusion ◽  
Strain Hardening Behavior ◽  
Element Study

Equal channel angular extrusion/pressing multipass simulations were carried for two routes, Route A and Route C, by using finite element code Abaqus/Explicit. Realistic parameters like strain hardening behavior of material, friction between the sample and die were considered for simulations. The strain homogeneity and deformation behavior of samples during multipass ECAE with different routes were studied. The deformation behavior of the sample processed through Route A is smooth. Accordingly strain homogeneity of the samples was more of a possibility with Route A than with Route C.

scholarly journals An Experimental Study of the Tension-Compression Asymmetry of Extruded Ti-6.5Al-2Zr-1Mo-1V under Quasi-Static Conditions at High Temperature

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1299
Author(s):  
Chen Zhang ◽  
Dongsheng Li ◽  
Xiaoqiang Li ◽  
Yong Li
Keyword(s):  
High Temperature ◽  
Strain Hardening ◽  
Yield Stress ◽  
Mechanical Response ◽  
Tensile Deformation ◽  
Uniaxial Tensile ◽  
Tensile Direction ◽  
Stress Asymmetry ◽  
Static Conditions ◽  
Tension Compression Asymmetry

The tension-compression asymmetry (TCA) behavior of an extruded titanium alloy at high temperatures has been investigated experimentally in this study. Uniaxial tensile and compressive tests were conducted from 923 to 1023 K with various strain rates under quasi-static conditions. The corresponding yield stress and asymmetric strain hardening behavior were obtained and analyzed. In addition, the microstructure at different temperatures and stress states indicates that the extruded TA15 profile exhibits a significant yield stress asymmetry at different testing temperatures. The flow stress and yield stress during tension are greater than compression. The yield stress asymmetry decreases with the increase in temperature. The alloy also exhibits TCA behavior on the strain hardening rate. Its mechanical response during compression is more sensitive than tension. A dynamic recrystallization phenomenon is observed instead of twin generated in tension and compression under high-temperature quasi-static conditions. The grains are elongated along the tensile direction and deformed by about 45° along the compressive load axis. Finally, the TCA of Ti-6.5Al-2Zr-1Mo-1V (TA15) alloy is due to slip displacement. The tensile deformation activates basal <a>, prismatic <a> and pyramidal <c + a> slip modes, while the compressive deformation activates only prismatic <a> and pyramidal <c + a> slip modes.

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