MICROSTRUCTURE EVOLUTION AND ACTIVIATION ENERGY IN SUPERPLASTICITY OF FeAl INTERMETALLIC ALLOYS
大晶粒FeAl合金超塑性变形的显微组织演变和变形激活能

The microstructure evolution of large-grained FeAl intermetallic alloys during superplastic deformation has been investigated. The superplastic deformation exhibits characteristics of conventional grain-fining. During superplastic deformation, the shape of original grains changes significantly at first, then many subgrain boundaries form in the grains, and after that the misorientation of every two adjacent subgrains increases. In a whole,it results in the dramatical decrease of the grain size of FeAl alloys after the supefplastic deformation to fracture. The deformation activation energy was measured to be about 370,290 and 260 kJ. mo-1 for Fe-36.5Al, Fe-36.5Al-1Ti and Fe-36.5Al-2Ti alloys,respectively, which are much lower than the creep activation energy previously measured in FeAl alloys. Low deformation activation energy indicates that the superplastic deformation process may be controlled by subgrain boundary and grain boundary diffusion.