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In order to improve the stress corrosion resistance of 316 stainless steel, a new technology was proposed and studied. The 316 stainless steel sample was treated by laser shock processing (LSP). The residual stress and microstructures of 316 stainless steel with and without LSP were measured and compared by the methods of X-ray, transmission electron microscopy (TEM) and Electron Back-ScatteredDiffraction (EBSD), and the strengthening mechanism was discussed. It showed that the high residual compressive stress introduced by laser shock processing was about-112 MPa. The TEM and EBSD results showed that severe plastic deformation and nanocrystals layer were formed by LSP, and the orientation of the grains had evident rotation in the process of plastic deformation. These helped to enhance the stress corrosion resistance of 316 stainless steel.

To clarify the role of carbon in improving the shape memory effect of Fe-Mn-Si-based shape memory alloys by thermomechanical treatments, we investigated the effect of optimum thermomechanical treatments on shape memory effect and microstructures of Fe-14Mn-5Si-8Cr-4Ni and Fe-14Mn-5Si-8Cr-4Ni-0.12C alloys. The Cr 23 C 6 particles in optimum thermomechanical-treated Fe-14Mn-5S-8Cr-4Ni-0.12C more effectively prevented collisions between stress-induced ε martensite bands than the residual α′ martensite in optimum thermomechanical-treated Fe-14Mn-5Si-8Cr-4Ni. This result is attributed to the thinner width of stress-induced ε martensite bands in optimum thermomechanical-treated Fe-14Mn-5S-8Cr-4Ni-0.12C compared to optimum thermomechanical-treated Fe-14Mn-5Si-8Cr-4Ni. In addition, the Cr 23 C 6 particles formed at more sites and provided more obstacles as compared with the residual α′ martensite. Accordingly, the recovery strain of Fe-14Mn-5Si-8Cr-4Ni-0.12C was higher than that of Fe-14Mn-5Si-8Cr-4Ni. It is concluded that carbon addition is beneficial to further improving the shape memory effect of Fe-Mn-Si-based shape memory alloys by thermomechanical treatments.