Improvement of the tribological properties of 316L/TI6AL4V layer structures produced with selective laser melting (SLM) by plasma oxidation

Selective Laser Melting (SLM) method is one of the metal additive production methods that allows the production of complex geometrical parts with a wide range of use from aircraft-body parts to biomechanical implants and prosthetic elements. The selected regions of the high-energy laser beam of the material contained in the production powder form are made by layer-layer melting. In this way, it is possible to obtain complex geometries which are costly and difficult to manufacture by conventional methods. Biomaterials produced especially from 316L stainless steel and Ti6Al4V are the most widely used biocompatible metallic implants and prosthetic elements. The high load capacity and reliable cost of the 316L stainless steel and the Ti6Al4V are used as bone screws, hip-knee prostheses and dental implants thanks to its excellent biocompatibility, improved mechanical properties and improved stability. However, the weakness of the tribological properties of these biomaterials and the high cost of Ti6Al4V are the most important disadvantages. In today's engineering applications, materials with advanced properties are required to be supplied at the most appropriate level. In this study, 316L stainless steel base material was produced by Selective Laser Melting method and then Ti6Al4V layer was formed in 316L structure with Selective Laser Melting. In this way, Ti6Al4V structure with improved biocompatibility has been obtained with low cost 316L and load-bearing capacity as base material. Plasma oxidation was applied to improve the tribological properties of the 316L / Ti6Al4V layered structure. The Ti6Al4V surface is plasma oxidized in 100% O2 gas medium at 650°C and 750°C for 1 and 4 hours. After these processes, pin-disc abrasion tests were performed to determine the micro-hardness measurements and tribological properties for the determination of the mechanical and tribological properties respectively. For determination of electrochemical properties, potentiostat / galvaniostat device and XRD, SEM and 3D Profilometer were used to determine the structural and abrasion properties of the materials. According to the data obtained, the best wear performance, corrosion resistance and oxide layer density were achieved by oxidation process at 750 ° C for 4 hours. 2019, 81 pages Keywords: Selective laser melting, 316L/Ti6Al4V layered structure, Plasma oxidation, Wear, Corrosion