MoNiCr nickel alloy for energy industry applications produced via additive manufacturing

Nacházelová Daniela - COMTES FHT a.s. (Czech Republic)

One of the considered concepts of Generation IV nuclear reactors is a molten salt-cooled reactor system. The components of the primary and secondary circuits of this energy source are exposed to extreme thermochemical stress, both in terms of the chemical effects of the molten salts at high temperatures and the creep loading conditions. Due to the unavailability of materials from which these components are typically manufactured, such as the Russian alloy HN80M, the French alloys EM-721 and EM-722, and the Chinese alloy GH3535, a nickel-based alloy named MoNiCr has been developed in the Czech Republic. The present work deals with the problem of production of MoNiCr alloy for use in additive manufacturing, where this material has a high tendency to form solidification cracks during additive manufacturing.  Particular attention must be paid to the quality of the feedstock material used in additive manufacturing, whether in the form of powder or wire. Final experimental samples were produced using the Directed Energy Deposition (DED) additive manufacturing technology. This modern manufacturing technique was selected due to its capability to produce complex and intricate component geometries, which are often unachievable using conventional manufacturing methods. The study focuses on the microstructure and mechanical properties of the material both after additive manufacturing and subsequent heat treatment.

Key words: MoNiCr, nickel alloy, additive manufacturing, Directed Energy Deposition (DED)