Assessment of diffusional mobilities in bcc Cu-Sn and bcc Cu-Zn alloys

The Cu-Sn-Zn alloy system is technically very important. Brass (Cu-Zn) and bronze (Cu-Sn) alloys have been used and developed for tools and components for over thousands of years and are still used in a wide range of applications like marine components, bearings, music instruments and for components in contact with corrosive media. Even though it is a very old and well-studied alloy system, there are only few studies that analyze Cu-Sn-Zn coating systems. Furthermore very basic properties like the diffusion through different phases are not studied in detail. In this work experimental diffusion data in the literature is critically reviewed. On the basis of these studies a diffusion mobility database for the bcc phase of the ternary Cu-Sn-Zn is presented. The database was established using the DICTRA-type (DIffusion Controlled TRAnsformation) diffusion modeling. The resulting curves for the interdiffusion coefficient for various alloy concentrations are then compared to available literature data. Furthermore, experiments from diffusion couples are recalculated for validation. A good fit of these experimental data could be realized using only few parameters.