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

摘要

The effect of high temperature heat treatments on the deformation behavior of ME21 extrusions was analyzed. Heat treatments at temperatures ＞ 475 ℃ result in significant grain growth with an associated enhancement of the rare earth (RE) texture component and in the growth of Mg_(12)Ce 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.