Influence of temperature and strain rate of tensile testing and grain size on yield point elongation in Al-Mg alloys.

Recently the method for obtaining ultra-fine grained metallic materials has developed using severe plastic deformation (SPD), such as equal channel angular pressing (ECAP), accumulative roll bonding (ARB), torsion straining, and warm multiple deformation (WMD) etc. In order to enhance thermal stability of ultra-fine grained aluminum alloys manufactured by SPD process, the addition of Sc and Zr elements has been considered to devise fine Al3Sc, Al3Zr and Al3(Scx Zr1-x) precipitates for inhibiting the grain growth. In this study, the microstructure evolution has been investigated in Al-Mg alloys with and without Sc and Zr addition during the warm multiple deformation process. In addition Al-Mg alloys were compressed at a strain rate of 10-1 sec-1 by two different routes, that is, route A and route B. Route A is to rotate the specimen throughout 90o around the vertical axis of loading direction at every pass. Route B is to rotate the specimen throughout 90o around the parallel axis of loading direction and then rotate it again as route A. The specimen deformed by route B had finer grain size and more uniform distribution of grains than those deformed by route A. When the warm multiple deformation process repeated up to 8 passes at 673 K, the specimen consisted of ultra-fine grained structure with the average grain size less than 3 μm. The superplastic behavior can also be observed at the high strain rate and low temperature regime.

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Influence of Mg Content, Grain Size and Strain Rate on Mechanical Properties and DSA Behavior of Al-Mg Alloys Processed by ECAP and Annealing

Materials Science Forum ◽

10.4028/www.scientific.net/msf.794-796.870 ◽

2014 ◽

Vol 794-796 ◽

pp. 870-875 ◽

Cited By ~ 3

Author(s):

Min Zha ◽

Yan Jun Li ◽

Ragnvald H. Mathiesen ◽

Christine Baumgart ◽

Hans J. Roven

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

Strain Rate ◽

Room Temperature ◽

Uniform Elongation ◽

Mg Alloys ◽

Lower Strain Rate ◽

Lower Strain ◽

Mg Content ◽

Al Mg Alloys

Ultrafine-grained (UFG) binary Al-xMg (x=1, 5 and 7 wt %) alloys were processed by equal channel angular pressing (ECAP) at room temperature via route Bccombined with inter-pass annealing. The effects of Mg content, grain size and strain rate on mechanical properties and dynamic strain aging (DSA) behaviour of the Al-Mg alloys upon tensile testing at room temperature were studied. An increase in Mg content from 5 to 7 wt % leads to a pronounced increase in strength and uniform elongation in both the as-homogenized and as-ECAP Al-Mg alloys. Thereby, the Al-7Mg alloy, either prior to or after ECAP processing, possess significantly higher strength and comparable or even higher uniform elongation than the more dilute Al-Mg alloys. However, the as-ECAP Al-Mg alloys exhibit significantly higher strength but little work hardening and hence rather limited uniform elongation. In general, decreasing grain size leads to significant increase in strength while dramatic decrease in ductility. Moreover, DSA serration amplitudes increase with reducing grain size in the micrometer range. However, the UFG Al-Mg alloys exhibit much less DSA effect than the micrometer scaled grain size counterparts, i.e. probably due to the high dislocation densities and special grain boundary features in the UFG materials. Also, the Al-Mg alloys, especially those with a UFG structure, exhibit higher strength and ductility at lower strain rate than at higher strain rate, due mainly to enhanced DSA effect and hence work hardening at a lower strain rate.

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Yield Point Elongation in Al-Mg Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.331-337.1303 ◽

2000 ◽

Vol 331-337 ◽

pp. 1303-1308 ◽

Cited By ~ 2

Author(s):

Hirosuke Inagaki ◽

Toshio Komatsubara

Keyword(s):

Yield Point ◽

Mg Alloys ◽

Yield Point Elongation ◽

Al Mg Alloys

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Effect of Heat Treatment on Yield Point Elongation and P-L Effect in 5182 Al-Mg Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.396-402.1049 ◽

2002 ◽

Vol 396-402 ◽

pp. 1049-1054 ◽

Cited By ~ 5

Author(s):

Shigeo Ohtani ◽

Hirosuke Inagaki

Keyword(s):

Heat Treatment ◽

Yield Point ◽

Mg Alloys ◽

Yield Point Elongation ◽

Al Mg Alloys

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On the strain rate dependence of the critical strain for plastic instabilities in Al-Mg alloys

Scripta Materialia ◽

10.1016/j.scriptamat.2016.11.037 ◽

2017 ◽

Vol 130 ◽

pp. 252-255 ◽

Cited By ~ 13

Author(s):

N. Chibane ◽

H. Ait-Amokhtar ◽

C. Fressengeas

Keyword(s):

Strain Rate ◽

Critical Strain ◽

Rate Dependence ◽

Mg Alloys ◽

Strain Rate Dependence ◽

Al Mg Alloys

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Effects of high Mg content and processing parameters on Portevin-Le Chatelier and negative strain rate sensitivity effects in Al–Mg alloys

Materials Science and Engineering A ◽

10.1016/j.msea.2020.139151 ◽

2020 ◽

Vol 779 ◽

pp. 139151 ◽

Cited By ~ 3

Author(s):

Chang-Hee Cho ◽

Hyeon-Woo Son ◽

Jae-Cheol Lee ◽

Kwang-Tae Son ◽

Ji-Woon Lee ◽

...

Keyword(s):

Strain Rate ◽

Strain Rate Sensitivity ◽

Rate Sensitivity ◽

Processing Parameters ◽

Mg Alloys ◽

Negative Strain Rate Sensitivity ◽

Mg Content ◽

Al Mg Alloys

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An Investigation of Cavitation in the Tensile Testing of a Spray-Cast Aluminum Alloy Processed by ECAP

Materials Science Forum ◽

10.4028/www.scientific.net/msf.503-504.83 ◽

2006 ◽

Vol 503-504 ◽

pp. 83-90 ◽

Cited By ~ 2

Author(s):

Megumi Kawasaki ◽

Cheng Xu ◽

Terence G. Langdon

Keyword(s):

Grain Size ◽

Aluminum Alloy ◽

Strain Rate ◽

Tensile Testing ◽

Ultrafine Grain ◽

Cast Aluminum Alloy ◽

Cast Aluminum ◽

Angular Pressing ◽

Cavity Development ◽

Spray Casting

A commercial aluminum 7034 alloy, produced by spray casting and having an initial grain size of ~2.1 μm, was subjected to equal-channel angular pressing (ECAP) through six passes at 473 K. In the as-pressed condition, the microstructure was reasonably homogeneous and the grain size was reduced to an ultrafine grain size of ~0.3 μm. This alloy contains MgZn2 and Al3Zr precipitates which restrict grain growth. In tensile testing at 673 K after processing by ECAP, an elongation of >1000% was achieved at a strain rate of 1.0 × 10-2 s-1 corresponding to high strain rate superplasticity. Quantitative cavity measurements were conducted on the specimens after tensile testing for both the as-received condition and after ECAP. These measurements reveal a significant number of small cavities in the samples and especially in the sample that exhibited a very high elongation. This paper describes the morphology of cavity development in the spray-cast aluminum alloy in both the as-received and as-pressed condition.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.488-489.27 ◽

2012 ◽

Vol 488-489 ◽

pp. 27-34 ◽

Cited By ~ 1

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.

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