|Title||Nanostructured Ni-Co alloys with tailorable grain size and twin density|
|Publication Type||Journal Article|
|Year of Publication||2005|
|Authors||Wu, BYC, Ferreira, PJ, Schuh, CA|
|Journal||Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science|
|Pagination||1927 - 1936|
We present an experimental approach to systematically produce nanostructures with various grain sizes and twin densities in the Ni-Co binary system. Using electrodeposition with various applied current densities and organic additive contents in the deposition bath, we synthesize nanostructured fee and hcp solid solutions with a range of compositions. Due to the low stacking fault energy (SFE) of these alloys, growth twins are readily formed during deposition, and by adjusting the deposition conditions, a range of twin boundary deinsities is possible. The resulting nanostructured alloys cannot be described by a single characteristic length scale, but instead must be characterized in terms of (1) a true grain size pertaining to general high-angle grain boundaries and (2) an effective grain size that incorporates twin boundaries. Analysis of Hall-Petch strength scaling for these materials is complicated by their dual length scales, but the hardness trends found in Ni-80Co are found to be roughly in line with those seen in pure nanocrystalline nickel.