Using methods of electron microscopy, we have discovered that combined electroexplosive alloying of nickel with boron and copper gives rise to a multilayer structure. An outer amorphous crystalline layer incorporating 2-3 nm nickel-and copper-boride, oxide, and boride-oxide crystallites is formed on the alloyed surface. The intermediate (subsurface) layer 1-2 μm thick is made up of NiB 12 and Ni 4 B 3 crystallites 120-130 nm in size, with boron-and copper-oxide particles observed along the grain boundaries. The underlying thick layer exhibits a cellular Ni-Cu-B melt crystallization structure grading initially into a high-rate dendritic crystallization structure and then into a granular structure. The electroexplosive alloying process is found to bring into existence a high scalar dislocation-density substructure in nickel crystallites both in the alloyed zone and in the adjacent heat-affected zone.
ASJC Scopus subject areas
- Physics and Astronomy(all)