Résumé
Austenitic 316L stainless steel can be used for orthopaedic implants due to its biocompatibility and high corrosion resistance. Its range of applications in that field could be broadened by increasing its wear and friction properties. Surface properties can be modified through coating or case hardening and the latter solution will be investigated here. Surface Mechanical Attrition Treatment (SMAT) is a surface treatment that enhances the mechanical properties of the material surface by creating a thin nanocrystalline layer. Further to this SMAT treatment, some specimens were heat treated to 425¢ªC to test the stability of the nanocrystalline layer at high temperature and others underwent a plasma nitriding process to further enhance their surface properties. Using electron backscatter diffraction, energy dispersive spectroscopy and transmission electron microscopy, we were able to characterise the microstructural evolution of the stainless steel after these different surface treatments. The microstructure features investigated here include thickness of the nanocrystalline layer, size of the grains within the nanocrystalline layer and depth of diffusion of the nitrogen atoms within the material.