Effects of Surface Preparation, Support Structures and Build Orientation on the Cyclic Stress-Strain Behavior of Inconel®718 produced by SLM 2019-01-0918
The flexibility in design offered by advanced additive manufacturing technologies makes these processes more and more attractive for automotive and aircraft applications, also for the realization of safety relevant metal components. The high strength, thermal resistant nickel-based alloy Inconel®718 is widely used for aircraft applications and its reduced machinability makes it an optimal candidate for AM technologies. The challenge, together with improving the process, is now to build the path that will bring AM technologies from rapid prototyping to series production. Therefore, it is essential to investigate additively manufactured materials and the effect that the following processes, like, for example, the surface preparation, have on their properties. Furthermore, while the static properties of additive manufactured Inconel®718, have been already investigated, this work aims to describe its cyclic stress-strain behavior, which will be used for a fatigue assessment.
Small scale flat specimens produced by Selective Laser Melting (SLM) of Inconel®718 powder are subjected to Incremental Step Tests in order to evaluate the cyclic stress-strain behavior of the material. To state the initial situation, specimens oriented along different directions with respect to the build platform are produced using standard process parameters. Individually adapted support structures, when needed, are subsequently removed. A part of the specimens is left in the as-built state, while others are subjected to mechanical polishing or to electro chemical polishing. The effects of surface preparation, support structures’ removal and build orientation on the cyclic stress-strain behavior of the material are evaluated and discussed.
Matilde Scurria, Benjamin Möller, Rainer Wagener, Jose Pena, Thilo Bein
Technische Universität Darmstadt, Fraunhofer Institute LBF