Optimization of MoNiCr Alloy Production Through Additive Manufacturing

Article with abstract: One of the concepts behind Generation IV reactors is a molten salt coolant system,where the materials for the reactor itself and for the primary and secondary circuit componentsare subjected to extreme chemical and thermal stresses. Due to the unavailabilityof these materials, a nickel–molybdenum alloy known as MoNiCr has been developedin the Czech Republic. This paper discusses the manufacturing process for the MoNiCralloy, covering conventional casting technology, forming, powder atomization, additivemanufacturing (AM) using the directed energy deposition (DED-LB) process, and finalheat treatment. Special attention was given to the quality of the input powders for additivemanufacturing, particularly regarding the optimization of the chemical composition, whichsignificantly influenced the quality of the additively manufactured components. AM enablesthe realization of complex structural designs that are critical for energy applications,despite the high susceptibility of the MoNiCr alloy to solidification cracking. ThroughAM, a test body was successfully produced with a maximum defect rate of 0.03% andthe following mechanical properties: a yield strength (YS) of 279 MPa, an ultimate tensilestrength (UTS) of 602 MPa, and an elongation (El) of 51%.