Hot Deformation Behavior and Microstructural Evolution of Al-Zn-Mg-Cu Alloy with Different Starting Structures

Abstract:

Hot Deformation behaviors and microstructural evolution of Al-Zn-Mg-Cu alloy with as-homogenized, as-forged and as-over-aged starting structures were studied at temperatures in the range of 300-420°C, strain rates in the range of 0.01-1s-1, and reductions in the range of 20%-80% by high-temperature compression tests. The flow stresses increase with increasing strain rate or decreasing temperature, which can be described by a hyperbolic-sine equation with the deformation activation energies of 246.35KJ/mol, 188.87KJ/mol and 178.25KJ/mol for the homogenized, the forged and the over-aged samples respectively. At the same deformation condition, the flow stress of the homogenized samples is greater than that of the forged and over-aged samples. For the homogenized samples, dendritic coarse grains elongated along the deformation direction, and interdendritic boundaries within coarse grains disappeared gradually due to diffusion at higher temperatures. When deformation is heavy, microstructures became into homogenous and geometric recrystallization occurs and new small grains appear within the severe elongated grains. For the forged samples, higher temperatures promote dynamic recrystallization. Recrystallized new small grains were developed along prior grain boundaries at large strains. For the over-aged samples, prior grains elongated along the deformation direction, and there is not much more dynamic recrystallized grains observed.

• Periodical: Advanced Materials Research (Volumes 941-944)
• Pages: 26-34
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.941-944.26
• Online since: June 2014
• Authors: Xiao Dong Zhao, Hui Qin Chen*, Jian Sheng Liu
• Keywords: Al-Zn-Mg-Cu Alloy, Hot Deformation, Microstructure Evolution

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