Deformation Conditions and Stability of the Basal Texture in Magnesium

2007 ◽  
Vol 539-543 ◽  
pp. 3401-3406 ◽  
Author(s):  
Talal Al-Samman ◽  
Günter Gottstein
Keyword(s):  
Strain Rate ◽  
Deformation Temperature ◽  
Texture Evolution ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Strain Rates ◽  
Basal Texture ◽  
High Deformation ◽  
Plane Strain Deformation ◽  
Electron Back Scattered Diffraction

Texture evolution and microstructure development of hot extruded pure magnesium and the magnesium alloy AZ31 deformed by plane strain deformation at select temperatures and strain rates were investigated using X-ray techniques, electron back scattered diffraction (EBSD) and optical microscopy. At a deformation temperature of 200 °C both materials showed a heterogeneous microstructure consisting of highly deformed zones appearing as huge grains or bands and of very small (~ 3 μm) grains. High temperature deformation (400 °C) gave rise to completely different microstructures. Changing of deformation conditions, i.e. the temperature and strain rate resulted in different final textures. At high deformation temperature and low strain rate the formation of a basal texture was suppressed.

Hot Deformation Behavior of 2519 Al Alloy during Isothermal Compression

2007 ◽  
Vol 546-549 ◽  
pp. 749-754 ◽  
Author(s):  
Hui Zhong Li ◽  
Xin Ming Zhang ◽  
Min Gan Chen ◽  
Ying Liu ◽  
Hui Gao
Keyword(s):  
Aluminum Alloy ◽  
Flow Stress ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Deformation Temperature ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Al Alloy ◽  
Strain Rates ◽  
Isothermal Compression

The deformation behavior of 2519 aluminum alloy was studied by isothermal compression by Gleeble-1500 simulator in the temperature range from 300 to 450°C under the strain rates of 0.01~10s-1. The results showed that the flow stress was controlled by strain rate and deformation temperature. The flow stress increased with strain rate and decreased with deformation temperature. The flow stress of 2519 aluminum alloy increased with strain and to the constant values at three strain rates of 0.01 s-1,0.1 s-1and1 s-1, indicating the dynamic recovery to occur. The flow stress decreased after a peak value with increase of strain at strain rate 10s-1 and deformation temperature higher than 350°C, showing partly dynamic recrystallization. The flow stress of 2519 aluminum alloy during high temperature deformation can be represented by Zener-Hollomon parameter.

Texture Formation during High Temperature Deformation of Al-3mass%Mg Solid Solution

2005 ◽  
Vol 495-497 ◽  
pp. 579-584 ◽  
Author(s):  
Kazuto Okayasu ◽  
Hiroshi Fukutomi
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Strain Rate ◽  
Deformation Temperature ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Strain Rates ◽  
Texture Formation ◽  
Compression Tests ◽  
Temperature Strain

Uniaxial compression tests were conducted on Al-3mass%Mg alloy under various temperatures and strain rates. High temperature yielding was observed at the temperatures higher than 623K. Texture examination elucidated that fiber textures are constructed in all the deformation conditions examined in this study. It was found that the kinds and intensities of texture components varied depending on deformation temperature, strain rate and the amount of strain.

High Temperature Deformation Mechanisms and Processing Map for Hot Working of Cast-Homogenized Mg-3Sn-2Ca Alloy

2010 ◽  
Vol 638-642 ◽  
pp. 3616-3621 ◽  
Author(s):  
K.P. Rao ◽  
Y.V.R.K. Prasad ◽  
Norbert Hort ◽  
Karl Ulrich Kainer
Keyword(s):  
Strain Rate ◽  
Processing Map ◽  
Volume Fraction ◽  
Flow Instability ◽  
Back Stress ◽  
Hot Working ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Strain Rates ◽  
Compression Tests

The hot working behavior of Mg-3Sn-2Ca alloy has been investigated in the temperature range 300–500 oC and strain rate range 0.0003–10 s-1, with a view to evaluate the mechanisms and optimum parameters of hot working. For this purpose, a processing map has been developed on the basis of the flow stress data obtained from compression tests. The stress-strain curves exhibited steady state behavior at strain rates lower than 0.01 s-1 and at temperatures higher than 350 oC and flow softening occurred at higher strain rates. The processing map exhibited two dynamic recrystallization domains in the temperature and strain rate ranges: (1) 300–420 oC and 0.0003–0.003 s-1, and (2) 420–500 oC and 0.003–1.0 s-1, the latter one being useful for commercial hot working. Kinetic analysis yielded apparent activation energy values of 161 and 175 kJ/mole in domains (1) and (2) respectively. These values are higher than that for self-diffusion in magnesium suggesting that the large volume fraction of intermetallic particles CaMgSn present in the matrix generates considerable back stress. The processing map reveals a wide regime of flow instability which gets reduced with increase in temperature or decrease in strain rate.

High-Temperature Deformation Behavior of the γ Alloy Ti-48Ai-2Cr-2Nb

1990 ◽  
Vol 213 ◽  
Author(s):  
Donald S. Shih ◽  
Gary K. Scarr
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
True Strain ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Strain Rates ◽  
Compression Tests ◽  
Uniform Deformation ◽  
Good Workability ◽  
Low Strain Rate

ABSTRACTThe hot-workability of a two-phase (γ+α2) alloy, Ti-48A1-2Cr-2Nb, has been studied by conducting isothermal compression tests to 0.8 true strain over the temperature range of 975–1200°C at strain rates between 1×l0−1 and 3×10−3s−1. A deformation map showing temperature, strain rate, soundness of deformation, and isostress contours was constructed. Good workability is found from the low temperature/low strain rate regime to combinations of high temperature and either high or low strain rate. The upper-limit flow stress for good workability is between 450 and 500 MPa. Deformation induced softening occurs at all conditions. SEM and TEM examinations of the deformed specimens reveal that non-uniform deformation takes place at all strain rates, but cracking occurs mostly at high strain rates (e.g. 1×10−1s−1), especially combined with low temperatures. The cracking appears to progress primarily along γ/α2interfaces. It is thought that non-uniform deformation develops channels of shear bands, which in turn promote localized recrystallization, thus accommodating higher strains.

Dynamic Deformation Response of G33 Steel under High Temperature

2015 ◽  
Vol 782 ◽  
pp. 61-70
Author(s):  
You Jing Zhang ◽  
Hong Nian Cai ◽  
Xing Wang Cheng ◽  
Shuang Zan Zhao
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Strain Rate ◽  
Shear Bands ◽  
Shear Zones ◽  
Adiabatic Shear ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Strain Rates ◽  
Adiabatic Shear Bands

The high temperature deformation and fracture behavior of ultra-high strength G33 steel under high strain rate compression are investigated by means of a split Hopkinson p ressure bar. Impact tests are performed at strain rates of 1000/s and 2200/s and at temperatures ranging from 25°C to 700°C. The SEM and TEM techniques are also used to analyze the microstructure evolution of the adiabatic shear band (ASB) and fracture characteristics of the deformed specimens at high temperature. The experimental results indicate that the flow stress of G33 steel is significantly dependent on temperatures and strain rates. The flow stress of G33 steel increases with the increase of strain rates, but decreases with the increase of temperatures. The strain rate sensitivity is more pronounced at the low temperature of 25°C. In addition, G33 steel is more liable to fracture at high temperatures than at 25°C. Observations of microstructure show two well-developed symmetric parabolic adiabatic shear bands on the longitudinal cross-section of the cylindrical specimen deformed at the temperature of 700°C and at the strain rate of 2200/s. Within the ASB, the width of the fine equiaxed grain structure is about 7μm. The size of those equiaxed grains is approximately 100nm. The fracture analysis results indicate that the ASBs are the predominant deformation and the specimens fracture along adiabatic shear bands. The fracture surfaces of the deformed G33 steel specimens are characterized by two alternating zones: rough dimple zone and relatively smooth shear zone. Further observations reveal that smooth shear zones consist of severely sheared dimples.

Hot Compressive Deformation Behavior of TC4-DT Titanium Alloy

2016 ◽  
Vol 849 ◽  
pp. 332-339 ◽  
Author(s):  
Jing Li ◽  
Li Wei Zhu ◽  
Xin Nan Wang ◽  
Yue Fei ◽  
Guo Qiang Shang ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Flow Stress ◽  
Strain Rate ◽  
Deformation Temperature ◽  
Strain Rate Range ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Deformation Degree ◽  
Deformation Behaviors ◽  
Gleeble 3500

Hot compressive experiments of TC4-DT titanium alloy were performed on Gleeble 3500 hot simulator. The influence of hot deformation parameters on high temperature deformation behaviors were investigated, including deformation temperature (938°C~1038°C), deformation degree and strain rate (0.01s-1~10s-1). The results indicated that the peak (σp) and steady-state flow stress (σs) of TC4-DT alloy decreased with the increase of deformation temperature under the same strain rate, especially under a high strain rate. The flow stress increased sharply then decreased and kept invariant finally with the increase of deformation degree. The flow stress increased with the strain rate increasing and exhibited different characteristics in different strain rate range. The optimum conditions obtained based on this investigation of TC4-DT alloy as follows: temperature was 938°C~1008°C, stain rate was 0.01s-1~0.1s-1.

High Temperature Deformation Behavior of 25Cr5MoA Nitriding Steel

2011 ◽  
Vol 399-401 ◽  
pp. 240-244
Author(s):  
Yue Zang ◽  
Shu Xia Li ◽  
Yi Kun Yang ◽  
Xue Ping Ren
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Deformation Temperature ◽  
True Strain ◽  
Strain Curve ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Deformation Degree

The high temperature deformation law of nitriding steel 25Cr5MoA over the strain rate range 0.001S-1~20S-1and temperature range 850°C to 1150°C was studied in the thermal simulation testing machine Gleeble-1500. Under a certain strain rate and a certain deformation degree, the flow stress decreased with the increase of deformation temperature. Work hardening of nitriding steel 25Cr5MoA was strong when the true strain was less than 0.2, otherwise the flow stress increased slowly, even dropped. High temperature deformation flow stress of nitriding steel 25Cr5MoA was influenced by the deformation temperature and strain rate. When the strain rate was 0.1S-1, true stress-true strain curve exhibited a dynamic recrystallization model, and with the increase of deformation temperature, peak flow stress shift left. When deformation degree was 0.69, the strain rate was 1S-1, and when deformation temperature was in the region of 850°C~1050°C, true stress-true strain curve exhibited a dynamic recovery model. And when the deformation temperature was in the region of 1100°C~1150°C, it showed a dynamic recrystallization model. Dynamic recrystallization diagrams of nitriding steel 25Cr5MoA were also established.

High Temperature Deformation Behavior and Microstructure Preparation of Cu-Ni-Si-P Alloy

2011 ◽  
Vol 704-705 ◽  
pp. 135-140 ◽  
Author(s):  
Yi Zhang ◽  
Bao Hong Tian ◽  
Ping Liu
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Deformation Temperature ◽  
Peak Stress ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Compression Tests ◽  
Hollomon Parameter ◽  
Temperature Ranges

The hot deformation behavior of Cu-Ni-Si-P alloy have been investigated by means of isothermal compression tests on a Gleeble-1500D thermal mechanical simulator in the temperature ranges of 873-1073 K and strain rate ranges of 0.01-5s-1. The results show that the dynamic recryatallization occurs in Cu-Ni-Si-P alloy during hot deformation. The peak stress during hot deformation can be described by the hyperbolic sine function. The influence of deformation temperature and strain rate on the peak stress can be represented using the Zener-Hollomon parameter. Moreover, the activation energy for hot deformation of Cu-Ni-Si-P alloy is determined to be 485.6 kJ / mol within the investigated ranges of deformation temperature and strain rate. The constitutive equation of the Cu-Ni-Si-P alloy is also established. Keywords: Cu-Ni-Si-P alloy; Hot deformation; Dynamic recrystallization; Zener-Hollomon parameter.

High Temperature Deformation and Corrosion Behavior of 2205 Duplex Stainless Steel under Low Strain Rate of 0.005 s-1

2014 ◽  
Vol 933 ◽  
pp. 27-31
Author(s):  
Yin Hui Yang
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
Duplex Stainless Steel ◽  
Deformation Temperature ◽  
Dynamic Recovery ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Flow Curves ◽  
2205 Duplex Stainless Steel ◽  
Low Strain Rate

The effect of deformation temperature on microstructure, flow stress and corrosion resistance of 2205 duplex stainless steel was investigated at low strain rate of 0.005 s-1. The flow curve analysis showed that the specimen was mainly characterized with dynamic recovery (DRV) at 850 °C, and the characteristic of dynamic recrystallization (DRX) was enhanced with deformation temperature increasing to 950 and 1050 °C, then flow curves presented steady state with characteristic of DRV at 1150 and 1250 °C. Microstructure analysis exhibited the austenite DRX at deformation temperatures of 1050 and 1150 °C. The specimens deformed at temperatures ranging from 850 to 1250 °C and strain rate of 0.005 s-1presented active-transpassive behavior, indicating faster corrosion rate compared with the as-received, which can be attributed to more ferrite (δ) and austenite (γ) grain boundaries or δ/γ phase boundaries formation.

Deformation Mechanism Maps for Al-Cu-Mg Alloys Micro-Alloyed with Tin

2011 ◽  
Vol 410 ◽  
pp. 283-286
Author(s):  
P.S. Robi ◽  
Sanjib Banerjee ◽  
A. Srinivasan
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Strain Rate ◽  
Deformation Mechanism ◽  
Base Alloy ◽  
Mg Alloy ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Strain Rates ◽  
Microstructural Investigation

High temperature deformation behavior of Al–5.9%Cu–0.5%Mg alloy and Al–5.9%Cu–0.5%Mg alloy containing 0.06 wt.% of Sn was studied by hot compression tests at various temperatures and strain rates. Addition of trace amounts of Sn into the Al–Cu–Mg alloy system resulted in a significant increase of flow stress for all conditions of temperature and strain rate. 100% and 89% of the flow stress values during hot deformation could be predicted within ± 10% deviation values for the aluminum alloys with and without Sn content, respectively, by artificial neural network (ANN) modeling. From the deformation mechanism maps and microstructural investigation, the safe process regimes for hot working of the base alloy was identified to be at (i) very low strain rate (< 0.003 s−1) at temperature < 450 °C, and (ii) high temperature (> 400 °C) with strain rate > 0.02 s−1. For the micro-alloyed alloy, it was at low strain rates (< 0.01 s-1) for the entire temperature range studied. Flow softening for both alloys was observed to be at low strain rates and was identified to be due to dynamic recrystallization (DRX). The metallurgical instability during deformation was identified due to shear band formation and/or inter-crystalline cracking.

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