Structural hardening pattern in high-energy layer implantation examined using nano-indentation techniques and grazing-incidence X-ray diffraction analysis

Nitrogen implantations into stainless steel lead to dramatic improvement of tribological properties, like wear resistance. The effects of such a treat ment at low implantation energy on mechanical properties are well documente d. The wear improvement is often correlated with the hardening of superfici al layers by precipitates and by compressive elastic stress in the substrat e matrix, due to the formation of a solid solution. The aim of this study i s to correlate GIXRD measurements and nanoindentation tests, performed on 3 16L surface, implanted with N-15 ions at high energy and dose (E=1MeV, d=10 (18)at.cm(-2)). We prove that the main mechanism in the surface strengtheni ng is the formation of expanded solid solution gamma (N) and of iron nitrid es Fe2N and Fe3N Located around the ion range.