MICROSTRUCTURE AND TENSILE PROPERTIES OF COMPACTED, MECHANICALLY ALLOYED, NANOCRYSTALLINE FE-AL

Data on mechanical properties of nanocrystalline materials have been l imited, due in part to the difficulty in producing consolidated nanocr ystalline materials of sufficient quantity for characterization and ev aluation. A second problem is consolidation and retention of the nanos tructure. A vacuum hot-pressing consolidation program has been develop ed to produce full-dense compacts from attrition milled, mechanically alloyed, nanograin micron-size particles of Fe-2 wt pct Al powder. The resulting compacts were of sufficient size to allow evaluation of mic rostructure, density, hardness, and tensile properties. The compacted microstructure was a composite of pure iron submicrograins and Fe-Al n anograin clusters. Tensile strength was found to be proportional to th e sample's density squared. For full-dense compacts, tensile strength of nanocrystalline compacts approaching 1 GPa was obtained.