Vacancy Wind Factor of Diffusion of 13 Binary Metallic Solid Solutions

A systematic analysis was performed on Manning’s vacancy wind factor for diffusion in 13 binary solid solutions for which experimentally measured tracer diffusion coefficient data collected from the literature are reliable and comprehensive. Some straightforward yet interesting observations are reported, including a value of ~ 1.85 for the diamond cubic Ge-Si binary solid solution. It is recommended that the vacancy wind factor not be included in the CALPHAD diffusion coefficient (mobility) assessments since the effects have essentially been included in the fitting parameters. For those who use diffusion coefficients directly (not mobility parameters), the factor may still be ignored for both fcc and bcc solid solutions since the maximum effect is only a 28% and 38% increase in the interdiffusion (chemical diffusion) coefficients, respectively. The factor may be included for low diffusion coefficient systems of diamond cubic phases at low temperatures and especially for those systems whose tracer diffusion coefficients differ by orders of magnitude.