Superplasticity in Coarse Grained Mg‐Al Class I Solid Solution of HCP Structure

Ito, Tsutomu; Saeki, Junya; Otsuka, Masahisa

doi:10.1002/9781118805497.ch38

Cited by 2 publications

(1 citation statement)

References 27 publications

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“…Al-Mg alloys such as 5083 aluminum alloys are base alloys, which are typical Class I or Class A solid solution alloys [10,11]. Superplastic-like large elongation occurring through intragranular deformation with solute drag creep as the main deformation mechanism, has been reported in the high-temperature deformation of Class I solid solution alloys [12][13][14][15][16][17][18][19][20][21][22]. In this paper, we discuss the phenomenological characteristics of superplastic-like large elongation occurring due to a transition of the high-temperature deformation mechanism in a fine-grained Class I Al-Mg solid solution alloy.…”

Section: Introductionmentioning

confidence: 99%

Superplastic-Like Elongation by Transition of Deformation Mechanism from Grain Boundary Sliding to Solute Drag Creep in Fine-Grained Al-Mg Solid Solution Alloy

Ito

Mizuguchi

2018

MSF

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It is widely accepted that the dominant deformation mechanism of fine-grained superplasticity is through grain boundary sliding (GBS) that occurs in fine-grained materials. However, it has been reported that in “Class I” solid solution alloys, superplastic-like behavior controlled by trans-granular deformation occurs by solute drag creep. In this study, we have investigated superplastic behavior in a fine-grained aluminum solid solution alloy with a thermally unstable microstructure. To obtain fine-grained microstructure, friction stir processing (FSP) was applied to a commercial 5083 aluminum (Al−Mg) alloy. An equiaxial fine-grained microstructure with a grain size of 7.4 μm was obtained after FSP; however, this microstructure was unstable at high temperatures. Generally, for fine-grained superplasticity or GBS to occur or continue, the fine-grained microstructure must be smaller than 10 μm during high-temperature deformation. However, a large elongation of over 200% was observed at high temperatures despite the occurrence of grain growth. From microstructural observations, it was determined that a fine-grained microstructure is maintained in the early stage of deformation, but at strain levels greater than 100%, trans-granular deformation occurs. The microstructural feature of this trans-granular deformation is similar to the deformation microstructure of solute drag creep observed in “Class I” solid solution alloys. This indicates that a change in the deformation mechanism from GBS to solute drag creep takes place during high-temperature deformation. Here, based on our observations on our model system, which is a thermally unstable aluminum solid solution alloy, we discuss the possibility of a superplastic elongation occurring by means of a transition of the deformation mechanism.

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Section: Introductionmentioning

confidence: 99%

Superplastic-Like Elongation by Transition of Deformation Mechanism from Grain Boundary Sliding to Solute Drag Creep in Fine-Grained Al-Mg Solid Solution Alloy

Ito

Mizuguchi

2018

MSF

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An electron-backscattered diffraction study of the texture evolution in a coarse-grained AZ31 magnesium alloy deformed in tension at elevated temperatures

Liu

2006

Metall Mater Trans A

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Electron-backscattered diffraction (EBSD) has been used to investigate the texture evolution during tensile deformation at temperatures between 673 and 773 K of a coarse-grained commercial AZ31 magnesium alloy. A weak (0001) fiber texture was initially present in the hot-rolled magnesium alloy plate. The [0001] directions of the grains spread 0 to 45 deg around the normal direction (ND) of the magnesium alloy plate. This pre-existing weak texture evolved during tensile deformation into a strong texture close to the {0001} Ͻ1 00Ͼ. The [0001] directions of the grains rotated toward the orientations perpendicular to the tension axis of the samples, indicating that the {0001} Ͻ11 0Ͼ slip system appeared to be the most active slip system, especially in the early stages of deformation. The EBSD Schmid-factor analysis revealed that, however, with an increase in strain and the rotation of the (0001) slip plane, the {11 2} Ͻ11 Ͼ slip system appeared to be more favorable. The {1 00} Ͻ11 0Ͼ and {1 01} Ͻ11 0Ͼ slip systems remained favored throughout the strains investigated, indicating that {1 00} and {1 01} are two important slip planes for cross slip using the Ͻ11 0Ͼ slip vector. It is found that the misorientation across one coarse grain (as high as 38.2 deg) is accommodated by low-angle grain boundaries (LAGBs). The formation of these LAGBs may be an intermediate stage of the coarse grain refinement that occurred during deformation. 2 1 1 2 1 2 1 2 3 2 2 1

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Superplasticity in Coarse Grained Mg‐Al Class I Solid Solution of HCP Structure

Cited by 2 publications

References 27 publications

Superplastic-Like Elongation by Transition of Deformation Mechanism from Grain Boundary Sliding to Solute Drag Creep in Fine-Grained Al-Mg Solid Solution Alloy

Superplastic-Like Elongation by Transition of Deformation Mechanism from Grain Boundary Sliding to Solute Drag Creep in Fine-Grained Al-Mg Solid Solution Alloy

An electron-backscattered diffraction study of the texture evolution in a coarse-grained AZ31 magnesium alloy deformed in tension at elevated temperatures

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