The Tensile Strength and Fracture Behavior of Partially Solidified Aluminum Alloys

Chu, M.G.; Granger, Douglas A.

doi:10.4028/www.scientific.net/msf.217-222.1505

Cited by 17 publications

(12 citation statements)

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“…[2,3] Twite et al [5] explained, in detail, that changes in liquidphase morphology occur following a specific sequence: (1) discontinuous liquid appears at triple boundaries, (2) liquid pockets spread along grain boundaries, and (3) continuous liquid films form. This evolution of morphology has been observed also by Chu et al [7] and van Haaften et al [4] by considering the evolution of the fracture surfaces, which exhibit (1) solid bridges at high solid fractions, (2) a mixture of solid bridges and liquid films, and (3) only liquid films. This evolution of the liquid distribution corresponds to an increase of the fraction of grain boundaries covered by the liquid, as defined by Reference 8.…”

Section: A Behavior Of Mushy State In Melting Conditionsmentioning

confidence: 68%

“…Essentially, three types of mechanical tests have been developed to study the rheological behavior of alloys in the semisolid state: tension, [2,[4][5][6][7][8][9][10] compression, [2,11] and shear. [2,10] Although the tensile test is the most difficult to perform owing to the very low strength and ductility of a semisolid alloy, it is the most interesting in the context of hot tearing since it allows testing the alloy in conditions close to those prevailing during the formation of this defect.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical Behavior of AA6061 Aluminum in the Semisolid State Obtained by Partial Melting and Partial Solidification

Giraud

Suéry

Coret

2010

Metall Mater Trans A

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International audienceThe tensile properties of a 6061 aluminum alloy have been studied in the semisolid state at large solid fractions. The tests have been carried out either after a partial melting treatment or after partial solidification. Results show the following: (1) the mechanical behavior depends on the liquid-phase distribution and, therefore, on the way the semisolid state has been achieved (melting or solidification); (2) there is a critical solid fraction range where the semisolid alloy is relatively brittle; and (3) the mushy alloy exhibits viscoplastic behavior with the occurrence of micro-superplasticity at low strain rate. Modeling of this behavior is carried out by considering either the area fraction of grain boundaries wetted by the liquid or a cohesion parameter of the solid phase, which depends on solid fraction and thermal treatment

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Section: A Behavior Of Mushy State In Melting Conditionsmentioning

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Mechanical Behavior of AA6061 Aluminum in the Semisolid State Obtained by Partial Melting and Partial Solidification

Giraud

Suéry

Coret

2010

Metall Mater Trans A

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“…Since cracks are usually the result of tensile strains, the tensile behavior of the alloy close to the end of solidification is of prime importance. This behavior was investigated recently in the case of various Al alloys, [5][6][7]9,[11][12][13][14][15] and it has been shown, in particular, that this behavior strongly depends on the thermal history experienced by the alloy. [5,6] It is indeed important to consider the behavior during partial solidification and not during partial melting, because cracks form during cooling of the alloy from the liquid state.…”

Section: Introductionmentioning

confidence: 95%

Shear Behavior of AA6061 Aluminum in the Semisolid State Under Isothermal and Nonisothermal Conditions

Giraud

Suéry

Coret

2011

Metall Mater Trans A

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International audienceThe shear behavior of a 6061 aluminum alloy was studied in the semisolid state at large solid fractions. The tests were carried out either at constant temperature after partial solidification (i.e., isothermal shear tests) or during solidification at low cooling rate (i.e., nonisothermal shear tests). In isothermal conditions, results show that (1) the mechanical behavior depends on the volume fraction of the solid phase present in the sample at the temperature of the test, (2) there is a critical solid fraction corresponding to the coalescence of the solid grains beyond which shear stress increases very sharply with increasing solid fraction, and (3) the mushy alloy exhibits viscoplastic behavior with a strain-rate-sensitivity parameter close to about 0.17. In nonisothermal conditions, results show that stress increases continuously with decreasing temperature whatever the strain rate. However, at high strain rate, it was observed that cracks developed when the solid fraction approaches 1, leading to a slower stress increase compared to that observed at low strain rate. Finally, modeling of this behavior is carried out by considering a cohesion parameter of the solid phase, which depends on solid fraction and strain rate

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“…[22] M'Hamdi et al [23] applied the spongelike model discussed previously in a two-phase modeling of aluminum direct chill casting, taking into account thermal straining and momentum transfer between the two phases. However, they did not use the evolution equation of the cohesion variable to simulate the effect of strain since a valid equation to (1) As-cast reheated bars in a tensile testing apparatus; [14,16,20,[32][33][34][35][36][37] (2) bars locally melted, cooled, and submitted to tensile deformation; and [38][39][40][41] (3) castings solidifying under tension. [42][43][44][45][46][47][48][49][50] The majority of investigators used the strain rate as the important mechanical variable to study the creep behavior in the semisolid interval.…”

Section: Introductionmentioning

confidence: 99%

A constitutive model for the tensile deformation of a binary aluminum alloy at high fractions of solid

Larouche,

Langlais,

et al. 2006

Metall Mater Trans B

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Tensile tests were performed on alloy Al-4.5 pct Cu with a solidification unit dubbed the direct chill surface simulator (DCSS) that simulates the primary cooling conditions encountered during the direct chill (DC) casting process of sheet ingots. The curves obtained showed a near linear increase of the load with strain up to the point where nonlinearity induced by hot tearing prevented further increase of the load. A constitutive model based on the Lahaie-Bouchard stress-strain theoretical model was generalized by assuming a nonsingular channel thickness distribution. This approach considers a fully lubricated arrangement that allows grain boundary sliding as the most important mechanism of accommodation. As the strain increases, the grain boundaries become more and more subjected to friction sliding and oppose a higher resistance than a fully lubricated sliding condition. This results in a gradual increase of stress with strain. The important variables of the model include solid fraction, channel thickness, geometric standard deviation, and creep law parameters. The model seems appropriate to correlate the tensile behavior of semisolid microstructures having up to 30 pct liquid phase distributed over a large spectrum of grain morphologies.

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The Tensile Strength and Fracture Behavior of Partially Solidified Aluminum Alloys

Cited by 17 publications

References 0 publications

Mechanical Behavior of AA6061 Aluminum in the Semisolid State Obtained by Partial Melting and Partial Solidification

Mechanical Behavior of AA6061 Aluminum in the Semisolid State Obtained by Partial Melting and Partial Solidification

Shear Behavior of AA6061 Aluminum in the Semisolid State Under Isothermal and Nonisothermal Conditions

A constitutive model for the tensile deformation of a binary aluminum alloy at high fractions of solid

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