Variable Strain Rate Forming Technique to Optimize Superplastic Forming of AA 5083 Using Multiscale Stability Analysis

2007 ◽  
Vol 10 (1) ◽  
pp. 45-65
Author(s):  
Naveen V Thuramalla ◽  
Mohammad A Nazzal ◽  
MK Kraisheh
Keyword(s):  
Stability Analysis ◽  
Strain Rate ◽  
Superplastic Forming

Influence of Superplastic Forming on Reduction of Yield Strength Property for Ti-6Al-4V Fine Grain Sheet and Ti-6Al-4V Standard

2016 ◽  
Vol 838-839 ◽  
pp. 171-176 ◽  
Author(s):  
P. Sartkulvanich ◽  
Don Li ◽  
Ernest Crist ◽  
K.O. Yu
Keyword(s):  
Yield Strength ◽  
Strain Rate ◽  
Strength Property ◽  
Grain Growth ◽  
Superplastic Forming ◽  
Influential Factor ◽  
Fine Grain ◽  
Sheet Materials ◽  
Forming Temperature

The SPF experiments were conducted on two sheet materials: Ti-6Al-4V Fine Grain Sheet (Ti-64 FGS) and Ti-6Al-4V Standard (Ti-64 STD) to investigate the influence of SPF conditions on the reduction of yield strength (YS) and change in microstructure for those two products. Results show that a) Ti-64 FGS has better formability at high testing strain rate than Ti-64 STD, b) initial YS values of Ti-64 FGS is 10% higher than Ti-64 STD, c) reduction of YS in Ti-64 FGS is 15-27%, which is much higher than 4-9% YS reduction for Ti-64 STD, d) the most influential factor on YS reduction is the forming temperature for Ti-64 FGS, but is the strain rate for Ti-64 STD, and e) microstructure pictures of initial Ti-64 FGS before forming is finer and more isotropic than Ti-64 STD, but Ti64 FGS shows more grain growth after SPF, which results in greater drop of yield strength.

scholarly journals SUPERPLASTIC DEFORMATION OF TWO PHASE MgLiAl ALLOYAFTER TCAP PRESSING.

2017 ◽  
Vol 23 (3) ◽  
pp. 215 ◽  
Author(s):  
Jan Marek Dutkiewicz ◽  
Stanislav Rusz ◽  
Dariusz Kuc ◽  
Ondrej Hilser ◽  
Paweł Pałka ◽  
...  
Keyword(s):  
Strain Rate ◽  
Rate Sensitivity ◽  
Superplastic Forming ◽  
Sensitivity Coefficient ◽  
Strain Rate Range ◽  
Two Phase ◽  
Angular Pressing ◽  
Slip Planes ◽  
Superplastic Properties ◽  
Grain Misorientation

<p>Magnesium based alloy containing 9 wt. % Li, 1,5 wt. % Al, composed of a + b (hcp + bcc) phases was cast under argon atmosphere and extruded at 350<sup>o</sup>C. Up to 3 passes of Twist Channel Angular Pressing TCAP deformation was applied at 160<sup>o</sup>C. TCAP tool consisted of helical part in horizontal area of the channel with angle of lead γ = 30° to simulate back pressure. The initial grain size of hexagonal a phase estimated at 30 mm decreased in following passes down to 6 mm and that of bcc b phase decreased after TCAP from initial 12 mm down to 5 mm. TEM studies after TCAP passes showed higher dislocation density in the b region than in the a phase. Crystallographic relationship (001) a || (110) b indicated parallel positioning of slip planes of both phases. Electron diffraction confirmed increase of grain misorientation with number of TCAP passes. Stress/strain curves measured at temperature 200<sup>o</sup>C showed superplastic forming after 1<sup>st</sup> and 3<sup>rd</sup> TCAP pass. Values of strain rate sensitivity coefficient <em>m</em> were calculated at 0.31 after 1 TCAP pass and increased after 3<sup>rd</sup> TCAP pass up to 0.47 for the strain rate range 10<sup>-5</sup> – 5 10<sup>-4</sup>. Increase of number of TCAP passes had positive effect on superplastic properties due to finer grains and increase of their misorientation;</p>

High-Temperature Deformation of Magnesium ElektronTM 43

2012 ◽  
Vol 735 ◽  
pp. 93-100
Author(s):  
Alexander J. Carpenter ◽  
Anthony J. Barnes ◽  
Eric M. Taleff
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Superplastic Forming ◽  
Solute Drag ◽  
Grain Boundary Sliding ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Fine Grained ◽  
Boundary Sliding

Complex sheet metal components can be formed from lightweight aluminum and magnesium sheet alloys using superplastic forming technologies. Superplastic forming typically takes advantage of the high strain-rate sensitivity characteristic of grain-boundary-sliding (GBS) creep to obtain significant ductility at high temperatures. However, GBS creep requires fine-grained materials, which can be expensive and difficult to manufacture. An alternative is provided by materials that exhibit solute-drag (SD) creep, a mechanism that also produces elevated values of strain-rate sensitivity. SD creep typically operates at lower temperatures and faster strain rates than does GBS creep. Unlike GBS creep, solute-drag creep does not require a fine, stable grain size. Previous work by Boissière et al. suggested that the Mg-Y-Nd alloy, essentially WE43, deforms by SD creep at temperatures near 400°C. The present investigation examines both tensile and biaxial deformation behavior of ElektronTM 43 sheet, which has a composition similar to WE43, at temperatures ranging from 400 to 500°C. Data are presented that provide additional evidence for SD creep in Elektron 43 and demonstrate the remarkable degree of biaxial strain possible under this regime (>1000%). These results indicate an excellent potential for producing complex 3-D parts, via superplastic forming, using this particular heat-treatable Mg alloy.

scholarly journals High Strain Rate Superplasticity in Al-Zn-Mg-Based Alloy: Microstructural Design, Deformation Behavior, and Modeling

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2098 ◽  
Author(s):  
Olga Yakovtseva ◽  
Maria Sitkina ◽  
Ahmed O. Mosleh ◽  
Anastasia Mikhaylovskaya
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Superplastic Deformation ◽  
High Strain ◽  
Flow Behavior ◽  
Constant Strain Rate ◽  
Superplastic Forming ◽  
High Strength ◽  
Strain Rate Range ◽  
Strain Rates

Increasing the strain rate at superplastic forming is a challenging technical and economic task of aluminum forming manufacturing. New aluminum sheets exhibiting high strain rate superplasticity at strain rates above 0.01 s−1 are required. This study describes the microstructure and the superplasticity properties of a new high-strength Al-Zn-Mg-based alloy processed by a simple thermomechanical treatment including hot and cold rolling. The new alloy contains Ni to form Al3Ni coarse particles and minor additions of Zr (0.19 wt.%) and Sc (0.06 wt.%) to form nanoprecipitates of the L12-Al3 (Sc,Zr) phase. The design of chemical and phase compositions of the alloy provides superplasticity with an elongation of 600–800% in a strain rate range of 0.01 to 0.6/s and residual cavitation less than 2%. A mean elongation-to-failure of 400% is observed at an extremely high constant strain rate of 1 s−1. The strain-induced evolution of the grain and dislocation structures as well as the L12 precipitates at superplastic deformation is studied. The dynamic recrystallization at superplastic deformation is confirmed. The superplastic flow behavior of the proposed alloy is modeled via a mathematical Arrhenius-type constitutive model and an artificial neural network model. Both models exhibit good predictability at low and high strain rates of superplastic deformation.

New Strategy for the Prediction of the Gas Pressure Profile of Superplastic Forming of Al-5083 Aluminium Alloy

2012 ◽  
Vol 735 ◽  
pp. 204-209 ◽  
Author(s):  
Nagore Otegi ◽  
Lander Galdos ◽  
Iñaki Hurtado ◽  
Sean B. Leen
Keyword(s):  
Strain Rate ◽  
Constant Strain Rate ◽  
Superplastic Forming ◽  
Pressure Profile ◽  
Bulge Test ◽  
Forming Process ◽  
Optimum Pressure ◽  
New Approach ◽  
Superplastic Alloy ◽  
New Strategy

This paper describes a new approach for identification of the optimum pressure history for SPF processes, based on mechanisms-based hyperbolic constitutive equations. This equation set has been modified to incorporate the effect of the damage behaviour the material suffers due to the cavitational evolution of Al-5083 superplastic alloy. A large deformation, multiaxial formulation of the constitutive equation set is implemented and applied to finite element modelling of a bulge test forming process to characterise the cavitation evolution behaviour in the bulge test, using conventional (constant strain rate) and the newly proposed (variable strain rate) strategy.

Quantitative Analysis of Instability for Superplastic Tension

2014 ◽  
Vol 941-944 ◽  
pp. 1505-1508
Author(s):  
Zhi Ping Guan ◽  
Ming Wen Ren ◽  
Pin Kui Ma ◽  
Po Zhao
Keyword(s):  
Strain Rate ◽  
Strain Path ◽  
Superplastic Forming ◽  
Uniform Strain ◽  
Deformation Condition ◽  
Al Alloy ◽  
Uniform Deformation ◽  
Rate Dependent ◽  
Strain And Strain Rate

In conventional analysis of instability, a rough prediction of uniform deformation was obtained due to taking material parameters as constants. In this study, the constitutive equation with varying parameters for Zn-5%Al alloy at 340 °C is employed to predict the critical values of uniform strain in tension based on Considere criterion and Hart criterion, respectively. It should address the factor of strain rate in the characterization of the capability of uniform deformation on superplastic alloys, or for that matter, on any rate-dependent material. Comparison and analysis indicated that the results on Hart criterion have the better predictability of uniform deformation than Considere criterion. The Considere criterion is dependent on strain path, while Hart crtierion is merely dependent on the values of strain and strain rate in tension, and is independent on the strain path or the deformation condition or the deformation history. Therefore, the uniform strain vs. strain rate relation can be taken as a quantitative reference for designing a reasonable strain path during superplastic forming with increase of formability and reduction of forming time.

Effects of Temperature, Strain Rate and Grain Size on Superplastic Behavior of Magnesium

2012 ◽  
Vol 488-489 ◽  
pp. 27-34 ◽  
Author(s):  
Muhammad Waseem Soomro ◽  
Thomas Rainer Neitzert
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Magnesium Alloys ◽  
Room Temperature ◽  
Superplastic Forming ◽  
Experimental Results ◽  
Superplastic Behavior ◽  
Influence Of Temperature ◽  
Effects Of Temperature ◽  
Temperature Strain

The influence of temperature, grain size and strain rate on superplasticity of magnesium is investigated. Different approaches are compared along with their experimental results to show the variation in the amount of superplasticity by varying above mentioned parameters. At room temperature magnesium alloys usually have poor formability but recent studies of some alloys such as ZE10, AZ31, AZ61 AZ60, AZ80 and AZ91 are pointing that by varying the temperature along with grain size and strain rate improved formability is possible or even superplastic forming of these alloys can be achieved to meet the demands of automotive, aircraft and other weight conscious industries.

High-strain-rate and low temperature superplastic forming of Zn-Al alloy

2003 ◽  
Vol 2003.11 (0) ◽  
pp. 391-392
Author(s):  
Tsutomu TANAKA ◽  
Li Fu Chaing ◽  
Sung Wook Chung ◽  
Koichi MAKII ◽  
Atsumichi KUSHIBE ◽  
...  
Keyword(s):  
Low Temperature ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Superplastic Forming ◽  
Al Alloy
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