Microstructure and tensile properties of compacted,mechanically alloyed,nanocrystalline Fe-AI

Data on mechanical properties of nanocrystalline materials have been limited, due in part to the difficulty in producing consolidated nanocrystalline materials of sufficient quantity for characterization and evaluation. A second problem is consolidation and retention of the nanostructure. A vacuum hot-pressing consolidation program has been developed to produce full-dense compacts from attrition milled, mechanically alloyed, nanograin micron-size particles of Fe-2 wt pet Al powder. The resulting compacts were of sufficient size to allow evaluation of microstructure, density, hardness, and tensile properties. The compacted microstructure was a composite of pure iron submicrograins and Fe-A1 nanograin clusters. Tensile strength was found to be proportional to the sample’s density squared. For full-dense compacts, tensile strength of nanocrystalline compacts approaching 1 GPa was obtained.