Abstract:The microstructural evolution of nanocrystalline Cu-10%Nb(mass fraction) alloy during mechanical alloying (MA) was investigated by using X-ray diffraction, optical microscopy(OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observation. Upon milling of Cu-Nb powders with coarse grains, the grain size is found to decrease gradually with lengthening milling time, and reach the minimum value (about 9 nm) after 100 h milling. The microstrain and the microhardness of the powders increase during the grain refinement. And Cu lattice parameter increases steadily over 100 h milling. The mechanisms of solid solution extension during milling were discussed. The results show that up to 10%Nb can be brought into solid solution by MA. The extension of solid solution is found to relate closely with the formation of nanocrystalline

Key words: mechanical alloying; nanocrystalline material; Cu-Nb alloy; microstructure