Significance of Imaginary Initial Strain Rate and Strain Rate Acceleration Factor in a Constant Load Creep

The aim of the present investigation was to determine and to compare the superplastic behaviour of the AA5083 (Al-Mg-Mn) alloy with Sc and Zr additions. The investigated alloys were processed to form sheets by conventional hot and cold rolling. The superplastic properties were determined with strain rates in the range of 1x10-4to 5x10-2s-1and forming temperatures of 350 to 550°C. The results showed that the alloy with about 0.4% Sc exhibited a high superplastic ductility across a wide temperature range and strain rates up to 1x10-2s-1. The highest elongations to failure of about 2000% were attained at 550°C and at an initial strain rate of 5x10-3s-1. However, the alloy with about 0.15% Zr exhibited elongations up to 600%. The FSP processed Al-4.5Mg alloy with combined addition of about 0.2% Sc and 0.15% Zr exhibited good superplastic properties at higher strain rates (> 1x10-2s-1) with elongations up to 1500%.

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Deformation and Fracture Behavior of 7039 Al Reinforced with B4C Particles at Elevated Temperature

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.351.65 ◽

2007 ◽

Vol 351 ◽

pp. 65-69 ◽

Cited By ~ 2

Author(s):

Cun Zhu Nie ◽

Jia Jun Gu ◽

Jun Liang Liu ◽

Di Zhang

Keyword(s):

Elevated Temperature ◽

Strain Rate ◽

Fracture Behavior ◽

Aluminum Matrix ◽

Rate Sensitivity ◽

Initial Strain Rate ◽

Initial Strain ◽

Temperature Deformation ◽

Uniaxial Tensile ◽

Deformation And Fracture

The elevated temperature deformation and fracture behavior of an 10vol%B4CP/7039 aluminum matrix composite plate was investigated by uniaxial tensile tests at temperatures ranging from573 to 773 K and at initial strain rates from 1x10-1 to 1x10-4s-1.The strain rate sensitivity exponent was found to be approximately 0.1-0.15 which was below that of a superplastic material. A maximum elongation of 116% was obtained at an initial strain rate of 10-1 s-1 and at a temperature of 773 K.

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On Phenomenon of Superplasticity in Fe3AL with Large Grains

MRS Proceedings ◽

10.1557/proc-364-115 ◽

1994 ◽

Vol 364 ◽

Cited By ~ 1

Author(s):

Aidang Shan ◽

Dongliang Lin

Keyword(s):

Tensile Test ◽

Strain Rate ◽

Elevated Temperatures ◽

Initial Strain Rate ◽

Optical Microscope ◽

Al Alloys ◽

Initial Strain ◽

Atomic Percent ◽

Maximum Elongation ◽

Grain Sizes

AbstractA variety of Fe3Al alloys including Fe-25Al, Fe-28Al, Fe-28Al-4Cr and Fe-28Al-2Ti (all in atomic percent) have been investigated by tensile test to find if these alloys could have superplasticity at elevated temperatures, the results revealed that all these alloys exhibited large elongations when the temperature is higher than 600°C. At 850°C , under appropriate initial strain rate, the elongation is all above 300%. For Fe-28Al-2Ti, the maximum elongation reached 585%. Maximum m values are all above 0.3. Initial grain sizes are bigger than 100μm but became finer after deformation. Fracture happened with necking but no cavities were found under optical microscope. Characteristics of this phenomenon were summarized and discussed.

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Application of High-Pressure Sliding for Grain Refinement of Al and Mg Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.667-669.91 ◽

2010 ◽

Vol 667-669 ◽

pp. 91-96 ◽

Cited By ~ 7

Author(s):

Kiyonari Tazoe ◽

Shuji Honda ◽

Z. Horita

Keyword(s):

High Pressure ◽

Strain Rate ◽

Grain Refinement ◽

High Pressure Torsion ◽

Initial Strain Rate ◽

Mg Alloys ◽

Initial Strain ◽

Mg Alloy ◽

Al Alloy ◽

Average Grain Size

An earlier study showed that high-pressure sliding (HPS) is effective for grain refinement of pure Al in a rectangular sheet form using the principle of high-pressure torsion. In this study, the HPS is applied for grain refinement of an Al-3%Mg-0.2%Sc alloy and an AZ61 Mg alloy. HPS was conducted under a pressure of 1 GPa with sliding distances of 10 to 30 mm at room temperature for the Al alloy and at 473 K for the Mg alloy The average grain size is ~300 nm for both the Al and Mg alloys, respectively. Tensile tests showed that a superplastic elongation of ~1500% is achieved in the Al-3%Mg-0.2%Sc alloy at 573 K with an initial strain rate of 3.3x10-3 s-1 and of ~600% in the AZ61 alloy at 573 K with an initial strain rate of 1x10-3 s-1.

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Effect of Rolling on Superplastic Behavior of an Al-Mg-Sc Alloy with Ultrafine-Grained Structure

Materials Science Forum ◽

10.4028/www.scientific.net/msf.838-839.416 ◽

2016 ◽

Vol 838-839 ◽

pp. 416-421 ◽

Cited By ~ 1

Author(s):

Andrii Dubyna ◽

Sergey Malopheyev ◽

Rustam Kaibyshev

Keyword(s):

Cold Rolling ◽

Strain Rate ◽

Rolling Direction ◽

Initial Strain Rate ◽

Warm Rolling ◽

Initial Strain ◽

Superplastic Behavior ◽

Ultrafine Grained ◽

Elongation To Failure ◽

Superplastic Properties

The superplastic behavior of a commercial aluminum alloy denoted as 1570 Al with a chemical composition of Al-6%Mg-0.5%Mn-0.2%Sc-0.07%Zr (in wt. %) and ultrafine-grained (UFG) structure produced by equal channel angular pressing at 300°C to a true strain ~12 was studied after final cold or warm rolling. The tensile specimens were machined along rolling direction and pulled up to failure in the temperature range of 250 to 500°C at strain rates ranging from 10-4 s-1 to 10-1 s-1. The specimens produced by warm or cold rolling exhibit different superplastic behavior. The material subjected to warm rolling exhibits excellent superplastic properties; the highest elongation-to-failure of ~1970% was recorded at a temperature of ~450°C and an initial strain rate of 1.4×10-1 s-1. On the other hand, the material subjected to cold rolling demonstrates moderate superplastic properties; the highest elongation-to-failure of ~755% appears at a temperature of ~300°C and an initial strain rate of 1.4×10-2 s-1.

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Superplasticity of an AA2519 Aluminum Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.838-839.278 ◽

2016 ◽

Vol 838-839 ◽

pp. 278-284

Author(s):

Ivan Zuiko ◽

Marat Gazizov ◽

Rustam Kaibyshev

Keyword(s):

Strain Rate ◽

Thermomechanical Processing ◽

Rate Sensitivity ◽

Initial Strain Rate ◽

Tensile Tests ◽

Sensitivity Coefficient ◽

Initial Strain ◽

Strain Rates ◽

Average Grain Size ◽

Elongation To Failure

A commercial AA2519 alloy with a chemical composition of Al-5.64Cu-0.33Mn-0.23Mg-0.15Zr (in wt. %) was subjected to two-step thermomechanical processing (TMP) providing the formation of fully recrystallized structure with an average grain size of ~7 mm in 3 mm thin sheets. Superplastic tensile tests were performed in the temperature interval 450-535°C and initial strain rates ranging from ~2.8 x 10-4 to ~6.0 x 10-1 s-1. The highest elongation-to-failure of ~750% appears at a temperature of ~525°C and an initial strain rate of ~1.4 × 10-4 s-1 with the corresponding strain rate sensitivity coefficient of ~0.46.

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Superplasticity and Fracture Morphologies during Superplastic Deformation of a Commercial TC6 Titanium Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.475-479.2961 ◽

2005 ◽

Vol 475-479 ◽

pp. 2961-2964 ◽

Cited By ~ 1

Author(s):

Miao Quan Li ◽

A.M. Xiong ◽

Z.Q. Zhang

Keyword(s):

Titanium Alloy ◽

Strain Rate ◽

Deformation Temperature ◽

Initial Strain Rate ◽

Failure Surface ◽

Initial Strain ◽

Tension Tests ◽

The Matrix ◽

Fracture Morphologies ◽

Main Pattern

Deformation behavior of a commercial TC6 titanium alloy at elevated temperature has been investigated using isothermal tension tests. By SEM, the fracture mechanism has been analyzed through the morphologies of failure surface. The superplasticity of the TC6 titanium alloy improves with an increase of deformation temperature and a decrease of initial strain rate. The optimal process parameters are the combination of 950 c o and 0.001s-1, and the limit elongation could reach 267%. The tough fracture is main pattern in the failure of the TC6 titanium alloy. The fracture begins at the boundaries between the matrix and the impurity, and it presents the much more tough fracture characteristic with an increase of deformation temperature and a decrease of initial strain rate.

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