Diffusion of Al during hot consolidation of FeAl

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 is also discussed. The diffusion coefficient of Al in FeAl is about 10−11 m2/s at 1150 °C for the material studied, with grain sizes between 0.5 and 5 μm. Grain boundaries are concluded to have a large effect on the global diffusion of Al in FeAl, even at the high temperature investigated here.