Mechanical properties and high-cycle fatigue strength of 3D printed inconel 718 alloy and effects of high-temperature exposure to corrosive atmosphere

摘要

3D printing is an advanced technology of manufacturing engineering components of complicated parts with a large market potential. This technology is particularly promising due to its potential possibilities of rapid manufacturing of components to their final shape and dimensions, which would significantly reduce production costs particularly due to reduction of production time and labour demands. This paper deals with results of an experimental programme aimed at investigation of selected properties of an Inconel 718 alloy manufactured using direct metal laser sintering (DMLS) method. The material is to be potentially used for manufacture of turbine blades for energy applications. Therefore, there are very high requests for mechanical properties and fatigue resistance at different conditions, which have to be investigated and demonstrated. It was shown that mechanical properties were quite strongly oriented considering the printing direction. In general, static mechanical properties were better than those of the material manufactured by conventional methods. Hardness and course of hardness did not significantly depend, as expected, on printing direction. In addition, hardness was higher in the material exposed to high temperature corrosive atmosphere. Reasons are discussed. Concerning high-cycle fatigue resistance, this characteristics was dependent on the printing direction. Fatigue strength of printed samples was higher than that of conventionally manufactured material in some cases. Damage mechanisms were investigated and they are discussed.