Grain refinement and superplasticity in a magnesium alloy processed by equal-channel angular pressing

Miyahara, Yuto; Matsubara, Kiyoshi; Horita, Zenji; Langdon, Terence G.

doi:10.1007/s11661-005-0034-2

Cited by 69 publications

(50 citation statements)

References 50 publications

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“…Figure. 1b. Effect of grain size on superplastic strain rate in Mg alloys; [7] datum points for ECAP [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] and HPT. [46][47][48][49] Figure 2.…”

Section: Figure Captionsmentioning

confidence: 99%

“…1[a] are taken from various reports for Al alloys, [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] and in Fig. 1 [b] there are similar sets of data for a range of Mg alloys [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] where the upper solid lines in Figs 1[a] and [b] show the predicted normalized strain rates derived using eq. [2].…”

Section: Introductionmentioning

confidence: 99%

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The Strength–Grain Size Relationship in Ultrafine-Grained Metals

Balasubramanian

Langdon

2016

Metall Mater Trans A

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Metals processed by severe plastic deformation [SPD] techniques, such as equal-channel angular pressing [ECAP] and high-pressure torsion [HPT], generally have submicrometer grain sizes. Consequently, they exhibit high strength as expected on the basis of the HallPetch [H-P] relationship. Examples of this behavior are discussed using data on Ti, Al-Mg 1 and Ni. These materials typically have grain size above ~50 nm where softening is not expected. An increase in strength is usually accompanied by a decrease in ductility. High strength and ductility can be achieved simultaneously by imposing high strains to give both ultrafine grain sizes and a high fraction of high-angle grain boundaries. An example is presented for a cast Al-7% Si alloy processed by HPT. In some cases, SPD may produce a fine grain size but also lead to a weakening due to microstructural changes as in ECAP of an Al-7034 alloy and HPT of Zn-22% Al. In SPD-processed materials, grain boundary segregation and nanostructural features are present which may lead to higher strengths than those predicted by the H-P relationship in some alloys having nano grain sizes.

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Section: Figure Captionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Strength–Grain Size Relationship in Ultrafine-Grained Metals

Balasubramanian

Langdon

2016

Metall Mater Trans A

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“…27 However, when m is about 0.3, the dominant mechanism is viscous process or intragranular glide process. 28 As for the m of 0.5, the GBS has been reported to be responsible for the superplastic behavior. 29 It has been reported that during the hot tensile testing of aluminum alloys, the elongation values of about 100%, corresponding to the strain-rate sensitivity of about 0.2-0.25, can be attributed to the dislocation climb mechanism.…”

Section: Strain-rate Sensitivitymentioning

confidence: 97%

Modeling the Hot Ductility of AA6061 Aluminum Alloy After Severe Plastic Deformation

Khamei

Dehghani

Mahmudi

2015

JOM

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Solutionized AA6061 aluminum alloy was processed by equal-channel angular pressing followed by cold rolling. The hot ductility of the material was studied after severe plastic deformation. The hot tensile tests were carried out in the temperature range of 300-500°C and at the strain rates of 0.0005-0.01 s À1 . Depending on the temperature and strain rate, the applied strain level exhibited significant effects on the hot ductility, strain-rate sensitivity, and activation energy. It can be suggested that the possible mechanism dominated the hot deformation during tensile testing is dynamic recovery and dislocation creep. Constitutive equations were developed to model the hot ductility of the severe plastic deformed AA6061 alloy.

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“…18 19, 20, 21, 22 23 Recently, researchers implemented processing routes combining two or more of th processes in successive steps. 24,25,26 These methods have been demonstrated to be successful for obtaining grain sizes of about 1 m and deformations larger than 400%.…”

Section: Introductionmentioning

confidence: 99%

Influence of grain size fluctuations on ductility of superplastic magnesium alloys processed by severe plastic deformation

Valle

Ruano²

2008

Materials Science and Technology

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The influence of fluctuations in the grain size along the gage length on ductility is analyzed in the superplastic regime. It is demonstrated that these fluctuations produce a similar effect to that produced by variations in the initial uniformity of the sample, leading to premature necking. In order to reach superplastic elongations of 400%, fluctuations in grain size of less than 0.5% between two zones of the gage length are required. As an example, the superplastic behavior of an AZ61 alloy, processed by severe plastic deformation, SPD, with a heterogeneous microstructure, is analyzed when the grain boundary sliding mechanism controls deformation. It is found that neck formation is related to bands of fine grains that are formed during SPD processing due to the mechanism of recrystallization by rotation. Under these circumstances grain refinement is rendered unsuccessful. The present investigation emphasizes the importance of the microstructure homogeneity in developing grain refinement processing routes.

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Grain refinement and superplasticity in a magnesium alloy processed by equal-channel angular pressing

Cited by 69 publications

References 50 publications

The Strength–Grain Size Relationship in Ultrafine-Grained Metals

The Strength–Grain Size Relationship in Ultrafine-Grained Metals

Modeling the Hot Ductility of AA6061 Aluminum Alloy After Severe Plastic Deformation

Influence of grain size fluctuations on ductility of superplastic magnesium alloys processed by severe plastic deformation

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