EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Ni-Superalloys possess good high temperature mechanical and physical properties especially in the range 550-1000°C. In addition, their resistance to oxidation makes this material as a seamless contender for gas turbine and jet engine components. This material can be also easily employed in additive manufacturing (AM) processes, in particular for Laser Powder Bed Fusion. However, the ideal fabrication of Ni-Superalloys via AM is still under investigation due to many issues either within the material or occurring due to the extreme physical conditions of AM. A list of aforementioned issues can be classified into 3 junctures: residual stress, defects and complex Laves phases related to the numerous alloying elements. The presence of these different phases can be detrimental to the understanding of the link between the microstructure and mechanical properties of additively manufactured alloys.
This study aims, then, to investigate a separate Ni based alloy system namely Ni20Cr which intends to form a multi-scale analysis of microstructure to mechanical properties-based relationship with successfully eliminating the issues related to Laves phases. This investigation comprises the aforementioned analysis based of monotonous tensile tests, cyclic tensile tests, and fatigue tests of Ni20Cr samples manufactured by LPBF. The study also encompasses the dislocation structure analysis using the ECCI technique over SEM, with high resolution imaging of dislocations and precipitates over STEM, in addition to chemical characterization using the EDS technique. Those analysis are also compared to conventional casted samples to highlight the behavior modifications related to LPBF.