The effect of surface mechanical attrition treatment on low temperature plasma nitriding of an austenitic stainless steel

Mahdi Chemkhi (1) , Delphine Retraint (1) , Arjen Roos (1) , Claude Garnier (1) , Laurent Waltz (2) , Clémence Demangel (3) , Gwénaëlle Proust (4)

1 LASMIS - Laboratoire des Systèmes Mécaniques et d'Ingénierie Simultanée
2 ThM2 - ThermoMécanique des Matériaux
3 CRITT-MDTS
4 School of Civil Engineering

The combined effect of superficial nanocrystallisation by SMAT (Surface Mechanical Attrition Treatment) followed by plasma nitriding on the mechanical properties of a medical grade austenitic stainless steel was studied. SMAT conditions were optimised to enhance nitrogen diffusion. Experimental observations (energy dispersive X-ray spectroscopy profiles, cross-sectional optical micrographs, phase analysis by X-ray diffraction and micro-hardness profiles) show that polishing away a very thin layer after SMAT and before nitriding significantly improves nitrogen diffusion into the substrate, yielding a 50% thicker nitrided layer. Possible causes for this improvement are discussed.

Mots clés: austenitic steels; plasma nitriding; nanocrystalline materials; SMAT; surface diffusion

Domaines: Matériaux; Matériaux et structures en mécanique [physics.class-ph]; Matériaux et structures en mécanique [physics.class-ph]; Mécanique des matériaux [physics.class-ph]; Mécanique des matériaux [physics.class-ph]

Mahdi Chemkhi, Delphine Retraint, Arjen Roos, Claude Garnier, Laurent Waltz, et al.. The effect of surface mechanical attrition treatment on low temperature plasma nitriding of an austenitic stainless steel. Surface and Coatings Technology, 2013, 221, pp.191-195. ⟨10.1016/j.surfcoat.2013.01.047⟩. ⟨hal-00855527⟩