Grain Refinement during Superplastic Deformation of Coarse-Grained Al-Mg-Cu Alloys

M.I. Cruz-Palacios; D. Hernández-Silva; L.A. Barrales-Mora; M.A. García-Bernal

doi:10.4028/www.scientific.net/MSF.509.75

Paper Titles

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Compressive Mechanical Properties of Nanostructured Intermetallic Alloys Al₃Ti-X (X = Mn or Fe)
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The Effect of Hot Rolling on Room Temperature Ductility of a NiAl Intermetallic Compound
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Grain Refinement during Superplastic Deformation of Coarse-Grained Al-Mg-Cu Alloys
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Strain-Resistivity Behavior of a Ti-45Ni-5Cu Shape Memory Alloy during Superelastic and SATWME Cycling
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Micro and Macromechanical Study of Stress-Induced Martensitic Transformation in a Cu-Al-Be Polycrystalline Shape Memory Alloy
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Thermal Stability, Structure and Mechanical Properties of TiSiN Coatings Prepared by Reactive DC Magnetron Co-Sputtering
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Joining of Silicon Nitride to Metal (Mo and Ti) Using a Cu-Foil Interlayer
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Grain Refinement during Superplastic Deformation of Coarse-Grained Al-Mg-Cu Alloys

Abstract:

In the present study the superplastic behavior of Al-6%Mg–0.5%Cu and Al–8%Mg– 0.5%Cu in a coarse grain size condition has been studied. The alloys are melted in an electrical furnace under argon atmosphere. The ingots (25 mm thick) are homogenized at 400 °C during 72 h and then rolled at 430 °C to a thickness of 5 mm. The mean grain size after rolling is 55 µm for the 6%Mg alloy and 61 µm for the 8%Mg alloy. Tensile test specimens are machined from the rolled plate in the rolling direction. Strain-rate-change tests at temperatures between 300 and 450 °C and strain rates between 1x10-4 and 1x10-1 s-1 are carried out to determine the strain rate sensitivity of the flow stress. Finally, elongation to failure tests are conducted at temperatures and strain rates where the alloys show a high strain rate sensitivity. Elongations higher than 390 % are obtained for the 8%Mg alloy. It is observed that the grip regions of the deformed samples show coarser grains than the regions near to the fracture surface. This means that grain refinement takes place during deformation, suggesting that the principal deformation mechanism is dislocation creep.