Microstructure evolution in nanocrystalline Cu-Nb alloy during mechanical alloying

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.

Microstructure evolution in nanocrystalline Cu-Nb alloy during mechanical alloying