Enhanced reactive diffusion of Zn in a nanostructured Fe produced by means of surface mechanical attrition treatment

Nanostructured pure Fe was produced on a coarse-grained (CG) sample using surface mechanical attrition treatment (SMAT). The formation behaviors of Fe-Zn compound layer were studied in nanostructured Fe electroplated with a Zn layer. In comparison with the CG sample, the Fe-Zn reaction in the nanostructured Fe showed an onset temperature decrease of similar to 21 degrees C and an increased enthalpy change of similar to 70%. The activation energy for the growth of Fe-Zn compound layer decreased from similar to 167.1 kJ mol(-1) in the CG sample to similar to 108.0 kJ mol(-1) in the SMAT sample. The grain size of the formed FeZn13 phase in the Zn/SMAT-Fe sample was much smaller than that in the Zn/CG-Fe sample after the same diffusion treatment. The enhanced reactive diffusion behaviors in the SMAT sample are attributed to the existence of a large number of grain boundaries in the nanostructured Fe. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.