NONEQUILIBRIUM SOLID-SOLUTION AND NANOCRYSTAL STRUCTURE OF FE-CU ALLOY AFTER PLASTIC-DEFORMATION UNDER PRESSURE

A nanocrystal structure and non-equilibrium solid solution of Fe-20 at .% Cu has been obtained after severe plastic deformation and additiona l heating. Thin disc samples were pressed at up to 11 GPa between Brid gman anvils and then deformed by rotating one anvil about the other. C u does not normally form a solid solution with Fe if the Cu concentrat ion exceeds 3 at.% and only Cu (f.c.c.) and Fe (b.c.c.) lines were rev ealed by X-ray diffraction from the initial master alloy. After deform ation (epsilon=6-4), broadened Cu and Fe lines were obtained. After fu rther deformation (epsilon=7-1) only b.c.c. Fe broadened lines were fo und. On additional heating up to 850-950-degrees-C, narrow fc.c. Cu an d b.c.c. Fe lines reappeared. The structure of the samples was investi gated by electron microscopy. After deformation to epsilon = 6.4, the sizes of the grains were 10-50 nm and beyond epsilon = 7-1, they were 5-20 nm. According to X-ray and nuclear gamma resonance data, a redist ribution of atoms and the formation of a solid solution of Fe-20 at.% Cu took place during deformation. A non-equilibrium solid solution of Fe-20 at.% Cu is also obtained after heating deformed epsilon = 6.4 sa mples up to 400-degrees-C.