Superplasticity Effect Demonstrated by Gas Forming Hot Bent AA5XXX Sheets into V-Shaped Trough Containing Uneven Concavities

2016 ◽  
Vol 838-839 ◽  
pp. 592-596
Author(s):  
Chia Hung Chen ◽  
Jian Yih Wang ◽  
Yiin Kuen Fuh ◽  
Shyong Lee ◽  
Chi Liu ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Strain Rate ◽  
Gas Pressure ◽  
Superplastic Material ◽  
Flow Properties ◽  
Metal Sheets ◽  
Processing History ◽  
Key Factor ◽  
Product Standard ◽  
Superplasticity Effect

Using low gas pressure as a tool to form metal sheets is certainly feasible. However, the intrinsic flow properties of metal sheet are often a key factor in determining degree of formability, which has not been emphasized or explained well. Most metals, for examples aluminum alloys, can be either superplastic or non-superplastic depending on their original processing history or route (consequently, yielding suitable microstructure) and forming conditions, i.e. mostly temperature and strain rate. This superplasticity effect is clearly demonstrated by gas forming superplastic AA5083 and non-superplastic AA5052 into a V-shaped deep trough containing uneven concavities. The results show the superiority of superplastic material when harsh product standard is required.

Experimental and numerical analysis of high strain rate behavior of aluminum alloys AMg-6 and D-16

2006 ◽  
Vol 134 ◽  
pp. 487-491 ◽  
Author(s):  
A. V. Abramov ◽  
A. M. Bragov ◽  
A. K. Lomunov ◽  
A. Yu. Konstantinov ◽  
L. Kruszka ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Aluminum Alloys ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Rate Behavior ◽  
Strain Rate Behavior ◽  
High Strain Rate Behavior

scholarly journals Анализ скоростных зависимостей критических напряжений в алюминиевых сплавах системы Al-Mg при ударных нагрузках

2020 ◽  
Vol 62 (11) ◽  
pp. 1749
Author(s):  
А.Д. Евстифеев ◽  
И.В. Смирнов ◽  
Ю.В. Петров
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloys ◽  
Strain Rate ◽  
Slight Reduction ◽  
Dynamic Stresses ◽  
Good Ductility ◽  
Critical Stresses ◽  
Critical Dynamic ◽  
Strain Rate Loading ◽  
Alloys Of The Al

Aluminum alloys of the Al-Mg system are widely used in automotive and aviation industries due to their combination of strength, good ductility and corrosion resistance. Increasing the percentage of magnesium leads to higher strength of the material with a slight reduction of ductility. Behavior of critical stresses in materials were studied under variable strain rate loading conditions. The possibility to predict critical dynamic stresses of materials based on a structural-time approach is discussed.

scholarly journals Effects of strain rate and CO2 on no formation in CH4/N2/O2 counter-flow diffusion flames

2018 ◽  
Vol 22 (Suppl. 2) ◽  
pp. 769-776
Author(s):  
Fei Ren ◽  
Longkai Xiang ◽  
Huaqiang Chu ◽  
Weiwei Han
Keyword(s):  
Strain Rate ◽  
Diffusion Flames ◽  
Numerical Study ◽  
Flame Temperature ◽  
Co2 Concentration ◽  
No Production ◽  
Counter Flow ◽  
Detailed Chemistry ◽  
No Formation ◽  
Key Factor

The reduction of nitrogen oxides in the high temperature flame is the key factor affecting the oxygen-enriched combustion performance. A numerical study using an OPPDIF code with detailed chemistry mechanism GRI 3.0 was carried out to focus on the effect of strain rate (25-130 s?1) and CO2 addition (0-0.59) on the oxidizer side on NO emission in CH4 / N2 / O2 counter-flow diffusion flame. The mole fraction profiles of flame structures, NO, NO2 and some selected radicals (H, O, OH) and the sensitivity of the dominant reactions contributing to NO formation in the counter-flow diffusion flames of CH4\/ N2 /O2 and CH4 / N2 / O2 / CO2 were obtained. The results indicated that the flame temperature and the amount of NO were reduced while the sensitivity of reactions to the prompt NO formation was gradually increased with the increasing strain rate. Furthermore, it is shown that with the increasing CO2 concentration in oxidizer, CO2 was directly involved in the reaction of NO consumption. The flame temperature and NO production were decreased dramatically and the mechanism of NO production was transformed from the thermal to prompt route.

Quantitative Detection of Hydrogen Gas Release during Slow Strain Rate Testing in Aluminum Alloys

2021 ◽  
Vol 1016 ◽  
pp. 568-573
Author(s):  
Keitaro Horikawa ◽  
Michiko Arayama ◽  
Hidetoshi Kobayashi
Keyword(s):  
Aluminum Alloys ◽  
Strain Rate ◽  
Local Strain ◽  
Hydrogen Sensor ◽  
Hydrogen Gas ◽  
Slow Strain Rate ◽  
Image Correlation ◽  
Quantitative Detection ◽  
Gas Release ◽  
Closed Chamber

We have developed a new testing device which is capable of detecting hydrogen gas release during slow strain rate tensile testing (SSRT) under ordinary pressure. The device is composed of an SSRT machine equipped with a closed chamber with an inspection window that is connected to gas chromatography with a semiconductor hydrogen sensor. Local strain distribution in the specimen during the SSRT is monitored dynamically with a digital image correlation (DIC) method. Hydrogen was pre-charged to aluminum alloys by means of friction in water process. Using the device, it was shown that hydrogen was released particularly in the stage of plastic deformation and fracture. In addition, the hydrogen gas release at the moment of fracture was clearly increased when the alloys were hydrogen-charged and tested at a slow strain rate. When we calculated hydrogen gas release from the fracture surface in Al-Zn-Mg base alloys tested at 3.3×10-6 s-1, the hydrogen amount was estimated to be 6.24×10-10 mol /mm2 in a hydrogen-uncharged alloy, and 1.30×10-9 mol / mm2 in a hydrogen-charged alloy.

scholarly journals Investigation of the Flow Properties of CBM Based on Stochastic Fracture Network Modeling

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2387 ◽  
Author(s):  
Bo Zhang ◽  
Yong Li ◽  
Nicholas Fantuzzi ◽  
Yuan Zhao ◽  
Yan-Bao Liu ◽  
...  
Keyword(s):  
Coal Seam ◽  
Gas Flow ◽  
Distribution Patterns ◽  
Element Model ◽  
Fracture Network ◽  
Gas Pressure ◽  
Computational Domain ◽  
Fracture Density ◽  
Flow Properties ◽  
Fracture Network Modeling

Coal contains a large number of fractures, whose characteristics are difficult to describe in detail, while their spatial distribution patterns may follow some macroscopic statistical laws. In this paper, several fracture geometric parameters (FGPs) were used to describe a fracture, and the coal seam was represented by a two-dimensional stochastic fracture network (SFN) which was generated and processed through a series of methods in MATLAB. Then, the processed SFN image was able to be imported into COMSOL Multiphysics and converted to a computational domain through the image function. In this way, the influences of different FGPs and their distribution patterns on the permeability of the coal seam were studied, and a finite element model to investigate gas flow properties in the coal seam was carried out. The results show that the permeability of the coal seam increased with the rising of fracture density, length, aperture, and with the decrease of the angle between the fracture orientation and the gas pressure gradient. It has also been found that large-sized fractures have a more significant contribution to coal reservoir permeability. Additionally, a numerical simulation of CBM extraction was carried out to show the potential of the proposed approach in the application of tackling practical engineering problems. According to the results, not only the connectivity of fractures but also variations of gas pressure and velocity can be displayed explicitly, which is consistent well with the actual situation.

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