Evolution of microstructures in materials induced by electropulsing.

Nanostructures were formed in several conventional materials under single electropulsing, that is nanophases of alpha-Cu(Zn) and beta'-(CuZn) in a cold-worked alpha-Cu(Zn) alloy, nanosized gamma-Fe in a low-carbon steel, nanosized alpha-Al in a superduralumin, and orientated nanosized TiC in a TiC/NiCr cermet. The mechanisms responsible for the above nanostructured transitions can be attributed to the competition of many factors induced by electropulsing, including high-rate heating, thermal stress, reduced thermodynamic energy barrier and high-rate electron impacting. Also, many low-energy dislocation configurations, twins and stacking faults were formed in the copper alloy and cermet under the electropulsing. Such evolution of defects was associated with the electrical, thermal and stress energies induced by the electropulsing.