Abstracts Book - IMRC 2018

• SE1-P008
EFFECT OF RE ON MICROSTRUCTURE AND TEXTURE
DEVELOPMENT OF MG ALLOYS DURING RECRYSTALLIZATION
ANNEALING
Xun Zeng 1 , Sangbong Yi 1 , Dietmar Letzig 1 , Karl Kainer 1
1 Helmholtz Zentrum Geesthacht, Magnesium Innovation Centre, Germany.
Lightweight magnesium alloys have received considerable attention for
applications in transportation sector for fuel efficiency and green environment.
However, the poor formability at low temperature, owing to strong basal-type
texture that develops during thermomechanical treatments, restricts further
processing of conventional Mg alloys sheets. Rare earth (RE) addition has been
proved an efficient way to weaken the texture with non-basal components.
Fundamental understanding of RE elements impact on microstructure and
texture development, however, is still lacking. In this study, the recrystallization
behaviour of Mg-RE cold rolled sheets is investigated. The RE element, such as
Nd, weakened the basal texture during recrystallization annealing. Addition of
Al or Zn into Mg-Nd alloy led to different microstructure and texture
development. The Mg-Al-Nd alloy showed a rapid recrystallization despite of a
large amount of precipitates. The area fraction of recrystallized grains reached
60% after the annealing at 350°C for 1 min, and 90% for 5 min. Recrystallized
grains in the Mg-Al-Nd ternary system inherited the basal type texture both in
nucleation and growth process. On the other hand, the Mg-Zn-Nd cold-rolled
sheets exhibited weak texture with the basal poles splitting into RD and
spreading into TD. The TD spread of the basal poles corresponded to the tensile
twinning. The Mg-Zn-Nd showed a significantly retarded recrystallization. A
preferential grain growth having a TD split texture component was observed,
accounting for texture weakening in this alloy.
Keywords: Mg alloys, Recrystallization, Texture
Presenting authors email: sangbong.yi@hzg.de