Laser surface alloying of 316L stainless steel : different hardening routes and related microstructures

The goal of this study is to investigate different hardening routes for 316L stainless steel by laser surface alloying. We have investigated the incorporation of hard submicronic particles of Tic, the precipitation of titanium carbide from mixtures of Ti and SiC and the formation of iron-chromium carbides by carbon incorporation. For each hardening route we present the microstructure and the hardness of the processed surface alloys and the conditions leading to the best compromise between highest hardness, best homogeneity and lowest occurence of cracks. From these results it can be reasoned that hardening by iron-chromium carbides is the best route and that this surface alloy is a good candidate for some tribological applications