Effect of high temperature heat treatments on the deformation behavior of Mg-2%Mn-0.7%Ce extrusions investigated by in-situ energy-dispersive synchrotron X-ray diffraction and elasto-plastic self-consistent modeling

The effect of high temperature heat treatments on the deformation behavior of ME21 extrusions was analyzed. Heat treatments at temperatures >475 °C result in significant grain growth with an associated enhancement of the rare earth (RE) texture component and in the growth of Mg12Ce precipitates and manganese containing dispersoids. Additionally, the number density of the dispersoids is decreased drastically. These microstructural changes produce a dramatic increase in the elongation to failure in room-temperature uniaxial compression tests. Thereby, elongations to failure up to 0.7 true strain where observed. The combination of in-situ energy-dispersive synchrotron X-ray diffraction and Elasto-Plastic Self-Consistent (EPSC) modeling shows that the texture modification increases the activity of slip-systems reducing the twin volume fraction. The deformation at high strains is predominantly realized by 〈c+a〉-pyramidal and 〈a〉-basal slip.