During the consolidation process of a fine-grained FeAl material local diffusion of Al and C takes place out from the FeAl phase into the encapsulating steel. Al and C transport was studied through recording of concentration profiles, using energy dispersive X-ray analysis with both scanning and transmission electron microscopy, together with microstructural developments and an associated model analysis. The role of processing environment was also considered. The diffusion coefficient of Al in FeAl was about 10−11m2/s at 1150C for the material studied, with grain sizes between 0.5 and 5μm. Grain boundaries were concluded to have a large effect on the global diffusion of Al in FeAl, even at the high temperature investigated here.

Diffusion of Al during Hot Consolidation of FeAl. H.Skoglund, M.Knutson-Wedel, B.Karlsson: Acta Materialia, 2006, 54[15], 3853-61