Resistance to strain-induced damage of an ultrafine-grained magnesium alloy deformed in superplastic conditions

Mussi, Alexandre; Blandin, J.J.; Salvo, Luc; Rauch, E.F.

doi:10.1016/j.actamat.2006.04.011

Cited by 47 publications

(22 citation statements)

References 43 publications

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“…The Mg alloys extruded at successive decreasing temperatures for each extrusion pass have been reported; [23,46] however, these authors provided no reason for their extrusion procedure. For the present research, the development of the multitemperature extrusion procedure is accomplished according to the guidelines obtained from the present results, as discussed earlier.…”

Section: Discussionmentioning

confidence: 97%

Effects of Processing Parameters on the Grain Refinement of Magnesium Alloy by Equal-Channel Angular Extrusion

Ding

Chang

Kao

2009

Metall Mater Trans A

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The Mg-3 pct Al-1 pct Zn (AZ31) alloy has been used as a model material for understanding the grain-refinement process of a Mg alloy fabricated by equal-channel angular extrusion (ECAE). The effects of ECAE processing parameters on grain refinement have also been studied; it was found that these effects are quite different from those for fcc metals. A multitemperature extrusion procedure has been developed, which can produce an ultrafine-grained AZ31 alloy having a grain size 0.37 lm. For the AZ31 alloy, this ultrafine-grained alloy has a record high strength accompanied by reasonably good tensile ductility. The success of the development of this ECAE procedure proves that ECAE can offer a good opportunity for the development of high-strength Mg alloys.

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Section: Discussionmentioning

confidence: 97%

Effects of Processing Parameters on the Grain Refinement of Magnesium Alloy by Equal-Channel Angular Extrusion

Ding

Chang

Kao

2009

Metall Mater Trans A

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“…[12] Indeed, it was shown in tensile testing of a superplastic AZ91 magnesium alloy that failure occurred by necking rather than by cavity interlinkage. [13] Accordingly, an understanding of the large elongations achieved in the present investigation requires an analysis of the nature of plastic flow during tensile testing.…”

mentioning

confidence: 99%

Record Superplastic Ductility in a Magnesium Alloy Processed by Equal‐Channel Angular Pressing

2008

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Superplastic metals generally have grain sizes in the range of ∼ 3-5 lm. [1] However, processing through the application of severe plastic deformation produces grain sizes in the submicrometer range [2] and, if these grains are stable at elevated temperatures, these materials may exhibit excellent superplastic properties. Grain refinement to the submicrometer level is readily achieved using Equal-Channel Angular Pressing (ECAP) [3] and there are numerous reports of the occurrence of superplastic ductilities in metallic alloys processed by ECAP [4] including in some magnesium alloys such as the ZK60 alloy (Mg-5.5 wt. % Zn-0.5 wt. % Zr). [5][6][7][8] Here we report the occurrence of exceptionally high superplastic elongations in a commercial ZK60 alloy processed by ECAP including a record tensile elongation of 3050 % after pressing through only 2 passes. This large elongation after a small number of passes suggests the potential for using the alloy in industrial superplastic forming operations.The tests were conducted using a magnesium ZK60 alloy and full details are given in the Experimental section. Figure 1 shows the appearance of specimens after pulling to failure following processing through different numbers of passes, M. It is apparent that elongations larger than 500 % are observed in all specimens independent of the number of passes thereby confirming the excellent superplastic properties of the ZK60 alloy. Furthermore, the specimens processed through 2 to 4 passes give elongations to failure larger than 2000 % and the specimen processed through 2 passes has an exceptionally high elongation to failure of 3050 %. This latter result is the largest superplastic elongation recorded to date in any magnesium alloy processed under any conditions with or without ECAP. Furthermore, reference to a recent detailed compilation of data for all alloys exhibiting superplasticity after ECAP [4] shows this is the highest elongation recorded in any alloy, including in highly ductile aluminum-based alloys, after processing by ECAP. An additional important conclusion from Figure 1 is that the ZK60 alloy does not follow the anticipated trend, reported earlier for an Al-3 % Mg-0.2 % Sc alloy, [9] of increasing ductility with increasing numbers of passes through the ECAP die.The true stress-true strain curves are given in Figure 2 for each of these specimens including for the as-received unprocessed condition where M = 0. These curves show there are important differences in the mechanical response, evident in both the initial flow stress and the subsequent level of strain hardening, which are dependent upon the numbers of passes and hence upon the imposed strain in ECAP. Thus, the initial flow stress decreases significantly from an as-received value of ∼ 30 MPa to ∼ 10 MPa after 1 pass and to ∼ 5 MPa after 2 passes. These differences are due to grain refinement during ECAP which leads to easier flow when testing in the re-COMMUNICATIONS ADVANCED ENGINEERING MATERIALS 2008, 10, No. 1-2

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“…Later it was found that the use of back-pressure [5,6], increasing the die angle [7,8], introducing an intermediate processing step by extrusion [9][10][11][12][13][14][15][16] or gradually decreasing the ECAP temperature [17,18] allow processing these alloys at low and moderate temperatures and produce significant grain refinement. A model for grain refinement of magnesium processed by ECAP was proposed [19,20].…”

Section: Introductionmentioning

confidence: 99%

Processing magnesium alloys by severe plastic deformation

Figueiredo

Aguilar

Cetlin

et al. 2014

IOP Conf. Ser.: Mater. Sci. Eng.

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Resistance to strain-induced damage of an ultrafine-grained magnesium alloy deformed in superplastic conditions

Cited by 47 publications

References 43 publications

Effects of Processing Parameters on the Grain Refinement of Magnesium Alloy by Equal-Channel Angular Extrusion

Effects of Processing Parameters on the Grain Refinement of Magnesium Alloy by Equal-Channel Angular Extrusion

Record Superplastic Ductility in a Magnesium Alloy Processed by Equal‐Channel Angular Pressing

Processing magnesium alloys by severe plastic deformation

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