Title: Grain boundary diffusion in severely deformed Al-based alloy,
Abstract: Grain boundary diffusion in severely deformed Al-based AA5024 alloy is
investigated. Different states are prepared by combination of equal channel
angular processing and heat treatments, with the radioisotope $^{57}$Co being
employed as a sensitive probe of a given grain boundary state. Its diffusion
rates near room temperature (320~K) are utilized to quantify the effects of
severe plastic deformation and a presumed formation of a previously reported
deformation-modified state of grain boundaries, solute segregation at the
interfaces, increased dislocation content after deformation and of the
precipitation behavior on the transport phenomena along grain boundaries. The
dominant effect of nano-sized Al$_3$Sc-based precipitates is evaluated using
density functional theory and the Eshelby model for the determination of
elastic stresses around the precipitates.