Tensile properties evaluation of additively manufactured AISI 316L thin wall and bulk material using various miniaturized specimen geometries

Abstract

Additive Manufacturing is an innovative technology, which allows creating structures of complex and unique geometries layer by layer. The mechanical properties of deposited objects can vary depending on their length, thickness and deposition orientation due to different cooling rates and various thermal conductivity. Austenitic steel AISI 316L, deposited using direct energy deposition technology, was an experimental material. The technology employs a high-power laser beam as an energy source for the powder melting. During the process, a powder is blown through the nozzle by protective gas into the processing area and subsequently molten. The aim of the study was to compare basic mechanical properties of the specimens extracted from a thin wall and a bulk material. The specimens were tested in horizontal and vertical orientations in relation to the build orientation in machined and as-deposited states. The tensile characteristics of proportional and non-proportional specimens were investigated within the study. The miniaturized tensile test specimens were employed in order to examine the strength and elongation of the experimental material. The mechanical testing results were complemented by microstructural analysis using a light microscopy (LM). Based on the obtained results, it can be concluded that the specimen proportionality affects not only the specimen elongation, but also the strength values of investigated material.