In-situ transmission electron microscopy determination of solid-state diffusion in the aluminum-nickel system

Using in-situ techniques, which couple energy dispersive spectroscopy mapping with a heated transmission electron microscope stage, solid-state diffusion of Ni-Al is studied in the temperature range 623–723 K with characteristic diffusion lengths of 1–100 nm. When the concentration profiles are analyzed using the Sauer-Freise method, and evaluated for 50 atomic percent Ni, the diffusion coefficients follow an Arrhenius temperature dependence: DNi→Al=8.2x10−9exp(−111kJ/RT)m2/s. Additionally, the formation of Al-rich intermetallic phases (Al3Ni & Al3Ni2) is shown to occur within heating durations of a second at the studied temperatures. EDS maps showing Ni-Al interdiffusion in the temperature range 623–723 K and the temperature dependence of diffusivity determined for 480–1140 K from this study and several previous studies. [Display omitted]