Influence of surface mechanical attrition treatment (SMAT) on the corrosion behaviour of AISI 304 stainless steel

• SMAT of 304 SS induced mechanical twins, martensite phase and dislocations.
• SMAT increased the surface roughness and corrosion rate of 304 SS in 0.6 M NaCl.
• Current–time curves indicate formation of defective passive film on SMATed 304 SS.
• Increase in roughness, martensite, dislocations nullify beneficial effect of SMAT.

The influence of surface mechanical attrition treatment (SMAT) on the corrosion behaviour of AISI 304 stainless steel in 0.6 M NaCl was studied. SMAT of 304 SS induced plastic deformation, enabled formation of mechanical twins and strain induced ά-martensite phase, increased the surface roughness and imparted compressive residual stress. SMAT caused a deleterious influence on the corrosion resistance of 304 SS in 0.6 M NaCl. Double log plots of current–time transients at 25 mV(SCE) indicate formation of defective passive film on SMATed 304 SS. Increase in surface roughness, strain induced martensite and dislocations nullify the beneficial influence of surface nanocrystallization.