The Influence of Tantalum on the Structure and Properties of AISI 316L Stainless Steel

Abstract—The influence of tantalum on the microstructure and properties of AISI 316L stainless steel produced by direct metal laser deposition was investigated. A powder mixture for direct metal laser deposition was prepared by adding tantalum powder to AISI 316L alloy powder at 5 and 95%, respectively. Metal samples were printed at laser power settings of 180 and 200 W. A comparison of height and width in longitudinal and transverse cross-sections was carried out, along with analyses of microstructure, microhardness, friction tests, and elemental composition for the two types of samples that were produced. The effect of tantalum on the dendritic structure was demonstrated. It was established that the tantalum content in the alloy during laser metal deposition significantly influences the volumetric shrinkage of the samples and promotes the formation of secondary arms on the primary arms of dendritic crystals. Tantalum particles act as nucleation centers and also contribute to grain refinement of AISI 316L stainless steel. During direct metal laser deposition, tantalum particles do not melt completely and partially retain their original structure, as confirmed by elemental analysis.