Suppression of chromium depletion and sensitization in austenitic stainless steel by surface mechanical attrition treatment

The effects of surface nanocrystallization via surface mechanical attrition treatment (SMAT) on degree of sensitization (DOS) of an austenitic stainless steel were investigated by means of double loop electrochemical potentiokinetic reactivation (DLEPR) test. The treated sample with grain size about 10 nm showed very low degree of sensitization value which can be considered as the non-sensitized material. This is mainly due to the formation of twin boundaries in the microstructure of the SMATed sample which weren't susceptible to carbide precipitation because of their regular and coherent atomic structure and extreme low grain boundary energy as compared with those of other grain boundaries.