Superplasticity-Like Behavior, Microstructures and Deformation Mechanism Map in Superlight Mg-6Li-3Zn Alloy

Abstract:

Mg-6Li-3Zn alloy sheets were prepared by melting and casting, and heavy rolling with a total reduction of 94%. The high-temperature mechanical behavior, microstructures and deformation mechanisms were investigated. The maximum elongation to failure of 300% was demonstrated at 623K and an initial strain rate of 1.67×10^-3s^-1. Observations by optical microscope, transmission electron microscope reveal that significant dynamic recrystallization and grain refinement occurred in banded grains at 573K and an initial strain rate of 1.67×10^-3s^-1, under which the subgrain contour was ambiguous and dislocation distribution was relatively uniform. It is shown by newly constructed deformation mechanism map that the high-temperature deformation mechanism in Mg-6Li-3Zn alloy sheet with banded grains at 573K and an initial strain rate of 1.67×10^-3 s^-1 is dislocation viscous glide controlled by lattice diffusion, the stress exponent is 3 (strain rate sensitivity exponent 0.33) and deformation activation energy is 134.8 kJ mol^-1, which is the same as the lattice diffusion activation energy of magnesium.

• Periodical: Advanced Materials Research (Volumes 189-193)
• Pages: 2504-2510
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.189-193.2504
• Online since: February 2011
• Authors: Fu Rong Cao, Ren Guo Guan, Hua Ding, Ying Long Li, Ge Zhou, Jian Zhong Cui
• Keywords: Mechanical Property, Mg-Li-Zn Alloy, Microstructure, Quasi-Superplasticity

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