Processing ODS Modified IN-625 Using Selective Laser Melting
Increasing the operating temperatures of power plant turbine generators is a universal method to increase the efficiency of steam and gas turbines. However, operating a plant at higher temperatures poses extreme challenges to the materials used, especially regarding oxidation, creep, thermal fatigue- and stress-corrosion cracking. The EU-OXIGEN project addresses these issues by the development of novel processing routes for ODS-modified materials, as this class of materials offers exceptionally high temperature strength, oxidation and corrosion resistance at temperatures exceeding 900°C. Additive manufacturing processes such as Selective Laser Melting are considered to enable their successful processing. First results on density of SLM-processed, mechanically alloyed ODS-modified Inconel-625 superalloy powders, are presented and compared to the processing conditions and results of gas atomized conventional Inconel-625 powders. Whereas for IN625 a wide and stable processing window was found, significant differences for the ODS variant in terms of the required laser energy input to reach density values >99% are found. Microstructural analysis of precipitates lead to the conclusion that the milling process for ODS variant is key to achieve good quality materials and results.