Enhanced atomic diffusion of Fe-Al diffusion couple during spark plasma sintering

The atomic diffusion of a Fe-Al system under spark plasma sintering was investigated at temperatures ranging from 773 to 873 K. A significant increase in the growth rate constant of Al13Fe4 and Al5Fe2 under the pulse current of spark plasma sintering was observed compared with the absence of current. The interdiffusion coefficient under pulse current was about 46 times higher than that without current at 873 K. The activation energy for the interdiffusion was 332 kJ/mol, which is higher than that without current of 155-190 kJ/mol. Although the diffusion kinetics were enhanced, the thermodynamics state is not altered. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.