STRUCTURE AND PROPERTIES OF SUPERFINE-GRAINED IRON COMPACTED OUT OF ULTRADISPERSE POWDER

The surface of the ultra-disperse iron powder particles was oxidized being in contact with the air. The powder was compacted under pressure plus torsion straining. The oxide film was found to dissolve during intensive deformation under pressure. A high degree of cold working of the resulting system Fe-O results in the formation of a fairly high-disperse structure during annealing. A spontaneous decay of the oversaturated solid solution at 600-degrees-C and the resulting microduplex structure comprised of the alpha-Fe grains sized 300 nm and FeO particles sized 200 nm leads to substantial strengthening of the alloy. The sample hardness reaches 4.7 GPa, which is higher than the hardness of original torsion strained samples.