Effect of Oxygen Content on the Processing Maps for Hot Deformation of OFHC Copper

2005 ◽  
Vol 128 (2) ◽  
pp. 158-162 ◽  
Author(s):  
Y. V. R. K. Prasad ◽  
K. P. Rao
Keyword(s):  
Strain Rate ◽  
Oxygen Content ◽  
Hot Deformation ◽  
Strain Rate Range ◽  
Ofhc Copper ◽  
Strain Rates ◽  
Rate Range ◽  
Self Diffusion ◽  
Controlling Mechanism ◽  
Effect Of Oxygen

Processing map for the hot deformation of high purity oxygen free high conductivity (OFHC) copper (2ppm oxygen) has been developed in the temperature range 600-950°C and strain rate range 0.001-100s−1. The map is compared with those published earlier on OFHC copper with higher oxygen contents (11ppm and 30ppm) with a view to evaluating the effect of oxygen content on the dynamic behavior of OFHC copper and the mechanism of hot deformation. The maps reveal that dynamic recrystallization (DRX) occurs over a wide temperature and strain rate range and is controlled by different diffusion mechanisms. In OFHC copper with 2ppm oxygen, the apparent activation energy for the DRX domain in the strain rate range 0.01-10s−1 and temperature range 600-900°C is estimated to be about 137kJ∕mole which suggests dislocation core diffusion to be the rate controlling mechanism. However, this domain is absent in the maps for OFHC copper with higher oxygen content due to the “clogging” of dislocation pipes by the oxygen atoms thereby preventing this short circuit diffusion process. At strain rates in the range 1-100s−1 and temperatures >700°C, the apparent activation energy is 73kJ∕mole suggesting that DRX is controlled by grain boundary self diffusion, and this domain expands with higher oxygen content in OFHC copper. At strain rates <0.01s−1 and temperatures >750°C, lattice self-diffusion is the rate controlling mechanism and this lower strain rate domain moves to lower temperatures with increasing oxygen content.

scholarly journals High Temperature Behaviors of a Casting Nickel-Based Superalloy Used for 815 °C

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 716
Author(s):  
Jiangping Yu ◽  
Donghong Wang ◽  
Jingyang Chen ◽  
Changlin Yang ◽  
Xin Hao ◽  
...  
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Peak Stress ◽  
Strain Rate Range ◽  
Deformation Condition ◽  
Strain Rates ◽  
Rate Range ◽  
Temperature Range ◽  
Nickel Based Superalloy ◽  
Deformation Behaviors

The hot deformation behaviors of the SJTU-1 alloy, the high-throughput scanned casting Nickel-based superalloy, was investigated by compression test in the temperature range of 900 to 1200 °C and strain rate range of 0.1–0.001 s−1. The hot processing map has been constructed with the instability zone. At the beginning of hot deformation, the flow stress moves rapidly to the peak value with the increased strain rates. Meanwhile, the peak stress is decreased with the increased temperature at the same strain rates. However, the peak stress shows the same tendency with the strain rates at the same temperature. The optimum hot deformation condition was determined in the temperature range of 1000–1075 °C, and the strain rate range of 0.005–0.1 s−1. The microstructure investigation indicates the strain rate significantly affects the characteristics of the microstructure. The deformation constitutive equation has also been discussed as well.

Tensile Stress-Strain Curves Modeling of Four Kinds of Solders with Temperature and Rate Dependence

2005 ◽  
Vol 297-300 ◽  
pp. 905-911 ◽  
Author(s):  
Xu Chen ◽  
Li Zhang ◽  
Masao Sakane ◽  
Haruo Nose
Keyword(s):  
Tensile Stress ◽  
Constitutive Model ◽  
Strain Rate ◽  
Constant Strain Rate ◽  
Tensile Tests ◽  
Strain Rate Range ◽  
Rate Dependence ◽  
Strain Rates ◽  
Stress Strain ◽  
Rate Range

A series of tensile tests at constant strain rate were conducted on tin-lead based solders with different Sn content under wide ranges of temperatures and strain rates. It was shown that the stress-strain relationships had strong temperature- and strain rate- dependence. The parameters of Anand model for four solders were determined. The four solders were 60Sn-40Pb, 40Sn-60Pb, 10Sn-90Pb and 5Sn-95Pb. Anand constitutive model was employed to simulate the stress-strain behaviors of the solders for the temperature range from 313K to 398K and the strain rate range from 0.001%sP -1 P to 2%sP -1 P. The results showed that Anand model can adequately predict the rate- and temperature- related constitutive behaviors at all test temperatures and strain rates.

scholarly journals Effect of Strain Rate on Compressive Behavior of a Zr-Based Metallic Glass under a Wide Range of Strain Rates

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2861
Author(s):  
Wenqing Li ◽  
Tieqiang Geng ◽  
Shaofan Ge ◽  
Zhengwang Zhu ◽  
Long Zhang ◽  
...  
Keyword(s):  
Amorphous Alloy ◽  
Yield Strength ◽  
Strain Rate ◽  
Amorphous Alloys ◽  
High Strain ◽  
Strain Rate Range ◽  
Strain Rate Effect ◽  
Strain Rates ◽  
Compressive Behavior ◽  
Rate Range

The strain rate effect on the mechanical behavior of amorphous alloys has aroused general interest. Most studies in this area have focused on quasi-static and high strain-rate compressive deformations. However, experimental results have been few, or even non-existent, under a moderate strain-rate loading. This article extends the traditional split Hopkinson pressure bar (SHPB) technique to characterize compressive deformation of an amorphous alloy at medium strain rates. The compressive behavior of Zr65.25Cu21.75Al8Ni4Nb1 amorphous alloy shows a negative strain rate effect on the yield strength with a quasi-static, moderate to high strain-rate range, and the fracture angle increases from 44° at 10−5 s−1 to 60° at 4000 s−1 as strain rate increases. Herein, we introduce a modified cooperative shear model to describe the compressive behavior of the current amorphous alloy under a broad strain rate range. The model predicts that the normalized yield strength will linearly descend with logarithmic strain rate when the strain rate is less than a critical strain rate, however, which rapidly decreases linearly with the square of the strain rate at high strain rates. The predicted data of the model are highly consistent with the current experimental results. These findings provide support for future engineering applications of amorphous alloys.

Characterization of Hot Deformation Behavior of Zr-4 Alloy in Material Application Area

2012 ◽  
Vol 578 ◽  
pp. 202-205
Author(s):  
Guo Qing Lin
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Flow Behavior ◽  
Strain Rate Range ◽  
Processing Maps ◽  
Peak Efficiency ◽  
Hot Deformation Behavior ◽  
Rate Range ◽  
Temperature Range

The hot deformation behavior of Zr-4 alloy was studied in the temperature range 650-900°C and strain rate range 0.005-50s-1 using processing maps. The processing maps revealed three domains: the first occurs in the temperature range 780-820°C and strain rate range 0.005-0.05s-1, and has a peak efficiency of 45% at 790°C and 0.005s-1; the mechanism is the dynamic recrystallization. The second occurs in the temperature range greater than 900°C and strain rate range 0.05-0.8s-1, and has a peak efficiency of 40% at 900°C and 0.5s-1, which are the domains of dynamic recovery. In addition, the instability zones of flow behavior can also be recognized by the maps in the temperature range 650-780°C and strain rate range 0.01-0.1s-1, which should be strictly avoided in the processing of the material. Zr-4 alloy is the material for pressure tube applications in nuclear reactors and has better strength and a lower rate of hydrogen uptake compared to other materials under similar service conditions.

Rate-Dependent Behavior and Constitutive Model of Polycarbonate at Strain Rate from 10-5 to 103 S-1

2011 ◽  
Vol 117-119 ◽  
pp. 434-437
Author(s):  
Wen Jun Hu ◽  
Xi Cheng Huang ◽  
Fang Ju Zhang ◽  
Cheng Jun Chen
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Temperature Dependent ◽  
Static Tests ◽  
Rate Range ◽  
Rate Dependent ◽  
Dependent Behavior

Uni-axial quasi-static tests at strain rates 10-5, 10-4, 10-3,10-2 and 10-1 s-1 and dynamic compressive tests at strain rates 1679, 2769,5000 and 8200 s-1 have been carried out to study the mechanical behavior for polycarbonate used in the avigation industry. The stress–strain curves of polycarbonate in the strain-rate range from 10-5 to 8200 s-1 have been obtained. The effects of the strain rate on yield phenomenon and rate-dependent mechanical behavior are discussed. A plastic flow law based on the DSGZ rate-temperature-dependent constitutive model was used to describe the mechanical behavior of polycarbonate in the strain-rate range from 10-5 to 103 s-1. The results at the six strain rates are in excellent agreement with the experimental data, which illustrates that the constitutive model can describe the mechanical behavior for polycarbonate at low and high strain rates perfectly.

Compressive strength of iceberg ice

2003 ◽  
Vol 81 (1-2) ◽  
pp. 191-200 ◽  
Author(s):  
S J Jones ◽  
R E Gagnon ◽  
A Derradji ◽  
A Bugden
Keyword(s):  
Grain Size ◽  
Compressive Strength ◽  
Strain Rate ◽  
Strain Rate Range ◽  
Air Bubbles ◽  
Strain Rates ◽  
Thin Sections ◽  
Rate Range ◽  
A Value ◽  
Wide Range

The uniaxial compressive strength of iceberg ice was determined over a wide range of strain rates from 10–8 to 10+1 s–1 at –10°C. It was found that for strain rates less than 10–4 s–1, strength increased in a power-law manner with strain rate. Above 10–4 s–1, the strength was essentially constant at 4 MPa, dropping slightly between 10–3 and 10–1 s–1, before rising again to a value of about 10 MPa at 10+1 s–1. Thin sections of the ice revealed a small grain size of about 3.5 mm and elongated air bubbles with a ratio of length to width of about 10. In the practical strain-rate range of interest, the maximum failure stress observed was 4.8 MPa. PACS No.: 62.20

Hot Deformation and Processing Map of C919 Aluminum Alloy

2015 ◽  
Vol 816 ◽  
pp. 810-817
Author(s):  
Yong Biao Yang ◽  
Zhi Min Zhang ◽  
Xing Zhang
Keyword(s):  
Aluminum Alloy ◽  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
Testing Machine ◽  
Strain Rate Range ◽  
Hot Compression ◽  
Strain Rates ◽  
Processing Maps ◽  
Compression Tests

The hot deformation behaviors of Aluminum alloy C919 were studied in the present investigation. The hot compression tests for C919 were carried out in the temperature range of 350°C~470°C and strain rates range of 0.001s-1~1s-1 using GLEEBLE-1500 thermal simulate testing machine. Optical microscopy (OM) was used for the microstructure characterization. The experimental results showed that the flow stress of C919 aluminum alloy decreased with increasing temperature and decreasing strain rates and the flow stress curves tended to increase at a strain rate of 1s-1 with increasing strain, while the flow stresses kept with increasing strain at lower strain rate. The alloys were more prone to dynamic recrystallization with decreasing strain rates during hot deformation. The hot compression behavior of C919 aluminum alloy can be described as hyperbolic sine function corrected Arrhenius relation. The processing maps for the alloy were built at a strain of 0.6. The instability deformation domain occurred at temperatures range from 350°C and 380°C and at a strain rate of 0.1-1s-1. Based on the processing maps and microstructure observations, the optimum hot-working parameters were determined to be at a temperature of 470°C in the strain rate range from 0.1-0.01s−1 for the C919 aluminum alloy.

scholarly journals Hot Deformation Behavior of Homogenized Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr Alloy via Hot Compression Tests

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2282 ◽  
Author(s):  
Zhimin Zhang ◽  
Zhaoming Yan ◽  
Yue Du ◽  
Guanshi Zhang ◽  
Jiaxuan Zhu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Hot Deformation ◽  
Strain Rate Range ◽  
Hot Compression ◽  
Test Machine ◽  
Compression Tests ◽  
Rate Range ◽  
Temperature Range

Mg-Gd-Y-Zn-Zr Mg alloys show excellent performance in high-end manufacturing due to its strength, hardness and corrosion resistance. However, the hot deformation and dynamic recrystallization (DRX) behaviors of Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr were not studied. For this article, hot compression behavior of homogenized high rare-earth (RE) content Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr (wt%) alloy was investigated by using the Gleeble-3500D thermo-simulation test machine under the temperature of 350–500 °C and the strain rate of 0.001–1 s−1. It was found that the high flow stress corresponded to the low temperature and high strain rate, which showed DRX steady state curve during the hot compression. The hot deformation average activation was 263.17 kJ/mol, which was obtained by the analysis of the hyperbolic constitutive equation and the Zener-Hollomon parameter. From observation of the microstructure, it was found that kink deformation of long period stacking ordered (LPSO) phase was one of the important coordination mechanisms of hot deformation at low temperature. The processing map with the strain of 0.5 was established under the basis of dynamic material model (DMM); it described two high power dissipation domains: one appearing in the temperature range of 370–440 °C and the strain rate range of 0.001–0.006 s−1, the other appearing in the temperature range of 465–500 °C and strain rate range of 0.001–0.05 s−1, in which dynamic recrystallization (DRX) mainly ocurred. The highest degree of DRX was 18% from the observation of the metallographic.

Hot Deformation Behavior and Processing Map of 25%SiCp/2009A1 Composite

2016 ◽  
Vol 849 ◽  
pp. 409-415 ◽  
Author(s):  
Shao Hua Wei ◽  
Yan Qiang Liu ◽  
Jun Hui Nie ◽  
Tao Zuo ◽  
Zi Li Ma ◽  
...  
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Constant Strain Rate ◽  
Material Model ◽  
Strain Rate Range ◽  
Deformation Condition ◽  
Processing Maps ◽  
Rate Range ◽  
Temperature Range ◽  
Dynamic Material Model

The hot deformation characteristics of 25%SiCp/2009A1 composite fabricated by powder metallurgy route were studied by thermal compaction testing on Gleeble-3800 hot-simulation machine in the temperature range of 370~520 °C and strain rate range of 0.01~10 s-1. The processing maps of 25%SiCp/2009A1 composites were developed on the basis of dynamic material model. The results show that the flow stress decreased with increasing deformation temperature at a constant strain rate, and increased with increasing strain rate at a constant temperature. The processing maps present unsteady zones at high strain rate (≥1 s-1). There are a few interfaces of particle-matrix separated and the particle itself cracked. There was significant dynamic recovery and dynamic recrystallization occurred in the higher temperature and lower strain rate region. The optimum hot deformation condition of the composites attained by the maps were in the temperature range of 450~490 °Cand in the strain rate range of 0.01~0.1 s-1.

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