Effects of precipitates on microstructure evolution and texture in Mg-Zn alloy during hot deformation

Abstract

The present research investigated ageing treatment on dynamic recrystallization and texture in Mg-Zn alloy by optical microscopy (OM), transmission electron microscopy (TEM) and electron backscattered diffraction (EBSD). Mg-6 wt.%Zn alloys were firstly solution and ageing treatment, and then the solutionized and peak-aged alloys were compressed at elevated temperature. The microstructure and texture were systematically investigated. Optical microstructure showed that ageing treatment prohibited dynamic recrystallization during deformation, which was because the precipitates inhibited dislocation movement and restricted the formation of deformation bands. The DRXed region and deformed region both contained typical basal texture with basal planes oriented perpendicular compression direction, but the recrystallized region showed a much weaker texture. The peak-aged alloy containing rod-shaped precipitates exhibited stronger texture intensity after dynamic recyrallization compared with the as-solutionized alloy, which was because the precipitates in the peak-aged alloy inhibited the lattice rotation of the newly formed DRXed grains or affected the microstructural evolution.