Shear mechanisms at 0–50% solid during equiaxed dendritic solidification of an AZ91 magnesium alloy

Gourlay, C.M.; Meylan, Bastian; Dahle, A. K.

doi:10.1016/j.actamat.2008.03.020

Cited by 58 publications

(49 citation statements)

References 28 publications

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“…Recently, shear-induced dilation has been measured in macroscopic semi-solid deformation experiments on Al-and Mg-alloys [9,11,22] and crystals have been observed to push each other apart under load during synchrotron radiography of semi-solid Al-and Fe-alloys [13,18]. These combined observations suggest that semi-solid alloys deform with fundamental similarities to granular materials such as water-saturated soils under certain combinations of microstructure and loading mode.…”

Section: Introductionmentioning

confidence: 86%

“…In the case of a globular morphology, semi-solid steels have been shown to be thixotropic [5] which has been attributed to the competition between agglomeration of globules with time and the breakdown of agglomerates during shear [1,6]. A range of other deformation mechanisms are also known to occur including viscoplastic deformation of the solid [4,7,8], fragmentation of the solid [7,9], and "granular" phenomena associated with rearrangement of the solid as discrete bodies [9][10][11][12][13]. Furthermore, semi-solid deformation is not homogeneous at the micro-scale [12,14,15] and strain readily localises [11].…”

Section: Introductionmentioning

confidence: 99%

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In situ study of granular micromechanics in semi-solid carbon steels

et al. 2013

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This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent repository link AbstractThe granular micromechanics of semi-solid steel at 80% solid are studied by synchrotron radiography. A particulate soil mechanics approach to image analysis shows that deformation occurs by the translation and rotation of quasi-rigid grains under the action of contact forces, and that the changes in directional fabric and grain-grain contacts occur by mechanisms similar to those of highly compacted soils including "locked sands". Grain-scale phenomena are then linked to the macroscopic displacement and strain fields and it is shown that shear-induced dilation is a fundamental response at both the grain and macro scales. Based on this, recommendations are made on future rheology experiments.

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Section: Introductionmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

In situ study of granular micromechanics in semi-solid carbon steels

et al. 2013

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“…[9][10][11] This is due to significant stresses acting on semi-solid microstructures. Gourlay et al 9,10) reported that semi-solid metallic alloys show the characteristics of saturated compacted granular materials such as dilatancy, which leads to volume expansion in response to shear. The deformation of semi-solid alloys causes strain localization into a shear band of increased liquid fraction, resulting in a segregation band after solidification.…”

Section: Introductionmentioning

confidence: 99%

“…[2][3][4][5][6][7][8] However, there are few researches on the mechanisms of macrosegregation formation caused by deformation in semi-solid alloys. 9,10) Segregation bands containing macrosegregation and porosity are often formed in high pressure die casting and centrifugal casting. [9][10][11] This is due to significant stresses acting on semi-solid microstructures.…”

Section: Introductionmentioning

confidence: 99%

“…9,10) Segregation bands containing macrosegregation and porosity are often formed in high pressure die casting and centrifugal casting. [9][10][11] This is due to significant stresses acting on semi-solid microstructures. Gourlay et al 9,10) reported that semi-solid metallic alloys show the characteristics of saturated compacted granular materials such as dilatancy, which leads to volume expansion in response to shear.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Shear Deformation Based on In-situ Observation of Deformation in Semi-solid Al–Cu Alloys and Water-particle Mixture

et al. 2013

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In-situ observation of deformation at the grain scale in semi-solid Al-Cu alloys has been carried out using synchrotron X-ray radiography. The deformed microstructure was characterized by the quantitative analysis of solid motion from the image sequences during shear in semi-solid Al-Cu alloys. The influence of solid particle shape on shear deformation was also examined by comparing with in-situ observation of deformation in water-polystyrene particle mixtures where the polystyrene particles are spherical with a diameter of 500 μm. In both semi-solid Al-Cu alloys and water-particle mixtures, solid particles located close to the shear plane developed an increasing component perpendicular to the shear plane, and a relatively high shear strain rate and decreased solid fraction was localized in a shear domain. The shear band width in semi-solid Al-Cu alloys (~10 mean particles diameter) was approximately two times wider than that formed in water-particle mixtures due to the difference in the solid particle shape.

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Evaluation of Magnesium Die‐Casting Alloys for Elevated Temperature Applications: Castability

Easton

Zhu

Abbott³

et al. 2015

Adv Eng Mater

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This paper presents a thorough evaluation of the castability of the most common Mg die‐casting alloys developed for elevated temperature applications. The alloys evaluated include AS31, AJ52, MRI153A, MRI153M, MRI230D, AXJ530, AE44, and AM‐HP2plus. Among the various alloys evaluated, AE44, MRI153A, and AS31 are found to have better castability than the other alloys. AM‐HP2plus also has acceptable castability, but it shows signs of hot tearing in some samples. The alloys containing significant levels of Ca, such as MRI153M, MRI230D, and AXJ530, tend to oxidize rapidly, leading to poor melt handling. The comparison of the castability of the selected alloys sheds some light on alloying elements that are of greatest importance in developing a castable alloy.

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Shear mechanisms at 0–50% solid during equiaxed dendritic solidification of an AZ91 magnesium alloy

Cited by 58 publications

References 28 publications

In situ study of granular micromechanics in semi-solid carbon steels

In situ study of granular micromechanics in semi-solid carbon steels

Characterization of Shear Deformation Based on In-situ Observation of Deformation in Semi-solid Al–Cu Alloys and Water-particle Mixture

Evaluation of Magnesium Die‐Casting Alloys for Elevated Temperature Applications: Castability

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