Grain boundary diffusion in severely deformed Al-based alloy

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.Comment: 13 pages, 7 figure

Low temperature features in the heat capacity of unary metals and intermetallics for the example of bulk aluminum and Al3_3Sc

We explore the competition and coupling of vibrational and electronic contributions to the heat capacity of Al and Al$_3$Sc at temperatures below 50 K combining experimental calorimetry with highly converged finite temperature density functional theory calculations. We find that semilocal exchange correlation functionals accurately describe the rich feature set observed for these temperatures, including electron-phonon coupling. Using different representations of the heat capacity, we are therefore able to identify and explain deviations from the Debye behaviour in the low-temperature limit and in the temperature regime 30 - 50 K as well as the reduction of these features due to the addition of Sc.Comment: 10 pages, 6 figures in total, paper submitted to Physical Review

Diffusion of Sn in polycrystalline α-Fe under pulsed magnetic field

The experimental investigations of Sn diffusion in ferromagnetic α-Fe within the pulsed magnetic field by X-ray diffraction analysis were performed. The pulsed magnetic field was found to influence significantly the diffusion coefficients of Sn in α-Fe