Effect of grain refinement on mechanical and electrochemical properties of ultra-fine grained AA1050 fabricated via ARB process

Effect of ARB process on mechanical and electrochemical properties of AM 1050 was investigated. AFM images represented nano-scale roughness of ARBed samples which decreased with increasing the number of ARB cycles. TEM micrographs indicated that with increasing the cycle number of ARB process, the grain size of samples decreased and UFG structure achieved. Based on TEM images, final grain size after nine cycles of ARB reached to 270 nm. Results of tensile test showed that as the number of ARB cycles increased, the mechanical characterization of samples improved. Potentiodynamic polarization and EIS plots revealed the enhancement of passive behavior of samples with increasing the cycle number of ARB process. Also, semiconducting behavior of passive films was investigated by using the Mott-Schottky analysis. The outcomes revealed that passive films of all samples behaved as n-type semiconductor, and donor density decreased with increasing cycle number of ARB process. Compared to annealed sample, it was found that electrochemical behavior of the ARBed samples improved by increasing the processing cycle number, which is due to grain refinement. (C) 2016 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.