|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Magnesium Technology 2018
||Large Strain Deformation Microstructures of Mg-3Al-1Zn Alloy
||Wei Li, Mert Efe, Dinakar Sagapuram
|On-Site Speaker (Planned)
A study has been made of large strain deformation behavior of Mg-3Al-1Zn alloy. A shear-based deformation method, cutting-extrusion, was used to impose controllable shear strains in the range of 1-2 over strain rates of 10<SUP>4</SUP> /s to 10<SUP>5</SUP> /s. At lower rates, flow localization and shear banding was observed at all strain levels studied. Shear bands are characterized by ultrafine grains (100-500 nm), while twinning is the main deformation mode in small-strain segments separating the bands. With increasing rate, a transition to uniform flow occurs due to adiabatic plastic heating and enhanced slip activity. Microstructures in uniform flow regime are homogeneous and dynamically recrystallized with a grain size of 1-5 microns. A phase diagram is developed that demarcates shear banded and uniform flow regimes and underlying microstructure mechanisms as a function of strain and strain rate. Strength, stored energy and recrystallization temperature of various deformed microstructures are also presented.