Theoretical and experimental study of the metallurgy of phase transformations in nickel superalloys for multiple thermal cycling conditions during DMD-based additive process

• Applicant: Dr.-Ing. Andrey Gumenyuk
• Subject Area: Materials in Sintering Processes and Generative Manufacturing Processes
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 449062083

The project devoted to description of metallurgical processes having places in DMD-based additive manufacturing of Ni-base Rene-type alloys and their relation to the appearance of liquation cracks in the re-solidified metal. The proposed research program composes experimental methods of generation of AM specimens together with the metallographic analysys of the resulting microstructure as well as development of the kinetic model capable to describe solidification microstructures at the conditions of multiple thermal cycling typical for AM-processes. Development of kinetic model of solidification based on diffusion-reaction approach supporting the finding of the metallurgical analysis of the microstructure in the weld metal is one of the key tasks within the project. The specific of the typical for DMD-process thermal conditions will be taken into account through the implementation of realistic measured and simulated thermal cycles and local temperature gradients into the micromodel.As an important part of the project, characteristic local temperature gradients and cooling rates for different geometries of build-up specimens as well as various scanning strategies corresponding to failure free microstructure are to be defined. Clearance of the metallurgical mechanisms of concurrent eutectic reactions (liquid - y-phase + y'-phase / liquid - y-phase + y'-phase + MC/M6C) upon AM conditions and their influence on hot cracking is another important issue, which will contribute to the understanding of mechanisms of hot crack formation during AM in Ni-base superalloy and determining of technological routes for their preventing.All these measures will help to promote AM technology for different industrial application and will increase a confidence to the safe application of AM-parts in safety relevant components

• DFG Programme: Research Grants
• International Connection: Russia
• Partner Organisation: Russian Foundation for Basic Research, until 3/2022
• Co-Investigator: Professor Dr.-Ing. Michael Rethmeier
• Cooperation Partner: Privatdozentin Olga Klimova-Korsmik, Ph.D., until 3/2022