GRAIN-GROWTH AND CHEMICAL ORDERING IN (FE,MN)(3)SI

Nanophase, chemically-disordered bcc alloys of Fe3Si and Fe2.7Mn0.3Si were prepared by mechanical attrition. Using x-ray diffractometry and Mossbauer spectrometry, the kinetics of grain growth and DO3 ordering in these two alloys were compared for a variety of annealing temperatu res and times. Compared to binary Fe3Si, in Fe2.7Mn0.3Si the ordering kinetics was accelerated bur the grain growth kinetics was retarded Bo th alloys had their highest grain boundary mobilities when they were c hemically disordered, and we suggest that the faster ordering kinetics in Fe2.7Mn0.3Si may suppress its grain growth. Another difference bet ween the two alloys was an early clustering of Mn atoms (possibly a gr ain boundary segregation).