Author/Authors :
Nikfahm، A. نويسنده Department of Technical Inspection Engineering, Abadan Faculty of Petroleum Engineering, Petroleum University of Technology, Abadan, Iran. , , Danaee، I. نويسنده Department of Technical Inspection Engineering, Abadan Faculty of Petroleum Engineering, Petroleum University of Technology, Abadan, Iran. , , Ashrafi، A. R. نويسنده , , Toroghinejad، M. R. نويسنده of Materials Engineering, Isfahan University of Technology, Isfahan, 8415683111, Iran Toroghinejad, M. R.
Abstract :
In this research accumulative roll bonding process as sever plastic deformation process was applied up to
8 cycles to produce the ultrafine grain copper. Microstructure of cycle 1, cycle 4 and cycle 8 investigated by TEM
images. By analyzing TEM images the grain size measured below 100 nm in cycle 8 and it was with an average grain
size of 200 nm. Corrosion resistance of rolled copper strips in comparing with unrolled copper strip was investigated
in acidic (pH=2) 3.5 wt. % NaCl solution. Potentiodynamic polarization and EIS tests used for corrosion resistance
investigations. The corrosion morphologies analyzed by FE-SEM microscopy after polarization test and immersion for
40 hours. Results show that the corrosion resistance decreased up to cycle 2 and increased after rolled for forth time.
The corrosion degradation was more intergranular in cycle 2 and unrolled counterpart. It was more uniform rather
than intergranular type in cycle 8. Corrosion current density in unrolled sample (2.55 ?Acm-2) was about two times of
that in cycle 8 (1.45 ?Acm-2). The higher corrosion rate in cycle 2 in comparison with others was attributed to unstable
microstructure and increase in dislocation density whereas the uniform corrosion in cycle 8 was due to stable UFG
formation.
