<Abstrate>

Mg-14 wt% Gd alloys in both as cast and as quenched conditions (T4) were subjected

to friction stir processing (FSP). The microstructure evolution, texture modification,

mechanical enhancement, as well as subsequent aging performance for both of the

two conditions were studied. Supplementary FSP experiments with cold air-cooling

(CFSP) were conducted for microstructure evolution comparison. During FSP, the

thermal histories are similar in regions away from the top center for both conditions.

The primary coarse grains were initially refined through repetition of geometric

dynamic recrystallization (GDRX). The refined grains then experienced subsequent

recovery and grain growth. Compared with as cast condition, generally larger grain

size, lower high angle grain boundary fractions, as well as much stronger texture

intensities leading to poorer ductility were generated in T4 condition after FSP. The

differences mainly lie on the pinning effect exerted by the Mg5Gd particle remnants.

The texture distribution depends on the final position strains and aging has little effect on it.
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