In-situ observations of recrystallization and microstructural evolution in cerium-containing rolled magnesium alloys

Abstract

The recrystallization and microstructural evolution of rolled Mg-2Zn-xCe (x = 0.2 and 0.6 wt%) were studied by combining annealing with in-situ electron backscatter diffraction (EBSD) analysis. Sequential EBSD orientation maps of the same microstructural patch were obtained at increasing temperatures, 298 K, 423 K, and from 473 K to 598 K in 25 K increments. In both alloys, the nucleation of new grains was first observed at 473 K, and recrystallization was complete by 573 K. It was found that greater Ce additions led to a higher fraction of recrystallized grains and an overall finer grain size. New grains with a misorientation angle-axis relationship of 60° about <101¯0>, 56° about <112¯0>, and 86° about <112¯0> were observed. Although the twin evolution during heating was not captured, the misorientation axis relationships along <101¯0>, <112¯0>, <101¯1> were characterized for the recrystallized grains. The misorientation angles were uniformly distributed between 30° and 90° in both alloys. The results are discussed and compared with Mg-3Al-1Zn (wt%).