Hot–extruded AZX611Mg alloy was multi–directionally forged under decreasing–temperature conditions (dMDFed) and followed by
room–temperature MDFing (rMDFing). Coarse initial grains were gradually fragmented by dynamic recrystallization during dMDFing and
ultrafine–grained structure was homogeneously developed over the cumulative strain of ÿÿÿ = 4.8. Additional rMDFing contributed to further
grain fragmentation due to kinking and mechanical twinning. Nevertheless, coarse precipitates in the as–hot–extruded samples and newly
formed fine precipitates during dMDFing impeded twinning. The achieved grain size appeared rather larger than that of the dMDFed AZ61Mg alloy.
While mechanical properties were drastically improved by simple dMDFing or rMDFing, the combined processes of dMDFing and rMDFing were not so effective to
induce additional strengthening. This was attributed to complicatedly combined effects of impediment of twinning by precipitates to grain fragmentation and fracture
caused by stress concentration at around precipitates/matrices.