Correlation between distribution of nitrogen atoms implanted at high energy and high dose and nanohardness measurements into 316L stainless steel

Ion implantation causes changes in surface composition or morphology of sol ids which yield to a modification of physical and particularly mechanical p roperties: such as hardness, Young's modulus and elastic recovery. The purp ose of this study is to focus on the effects occurring during the annealing process of stainless steel 316L samples implanted with high energy (1 MeV) nitrogen ions at high dose (10(18) N cm(-2)). From nuclear reaction analys is (NRA) measurements, the unusual shape of N distribution is discussed in terms of diffusion and precipitation mechanisms and correlated with the phy sical and chemical modifications observed with glancing incidence X-ray dif fraction (GIXRD). Finally, from nanoindentation measurements, the real hard ness profile is extracted using the Buckle's model eliminating the substrat e effect. For each specimen, we show that the hardness is the sum of two te rms, the first being related to nitrogen concentration and the second to va rious strengthening mechanisms depending on temperature. (C) 2001 Elsevier Science B,V. All rights reserved.