Surface treatment response of AISI 2205 and AISI 304L steels: SMAT and plasma-nitriding

The surface behaviour of surface mechanical attrition treated (SMATed) and plasma-nitrided AISI 2205 and AISI 304L steels was investigated in the present study. The intersection of the mechanical twins formed the submicron-size rhombic blocks in the surface region of the SMATed AISI 304L steel. However, such microstructural feature was absent in the SMATed AISI 2205 steel. The improvement in the surface-hardness due to the SMAT was about 70-80% for AISI 2205, and more than 100% for AISI 304L steel. The nature of passive film formed on the AISI 2205 steel was different from the AISI 304L steel. Passive film formed on the SMATed AISI 304L steel was relatively more unstable than that of the AISI 2205 steel at an elevated electric-potential and in a plasma environment. The plasma-nitriding response was affected due to the different passivation behaviour of the SMATed, and non-SMATed steels.