Education and Training Series #60: Development of an Austenitic/Martensitic Gradient Steel Connection by Additive Manufacturing

These webinars, organised by the GIF Education and Training Working Group are streamed live monthly. The recordings and slide decks are accessible after the webinar on this website. These webinars cover a very broad range of technical and policy related topics. At the end of 2023 they have been viewed by more than 15000 people (approximately half of the views during the live streams and the other half views being of the archives on the public GIF website). In total, the GIF webinars have reached Generation IV enthusiasts, scientists, and engineers in more than 80 countries.

These webinars are organised and hosted by the GIF Education and Training Working Group (ETWG). 

Metal additive manufacturing is already used to build parts for aeronautic or medical applications. The power generation industry is just beginning to use these new technologies to replace or repair parts. Dr Villaret’s work aims to make this technology available for nuclear industry and especially for GEN IV reactors where technological innovation will find all their meaning. Flore Villaret's PhD work focuses on an application of additive manufacturing to obtain bimetallic junctions. Such junctions between two different metals are very common in nuclear reactors, but they are often difficult to realize. The example studied is a junction between an austenitic stainless steel 316L and a martensitic steel Fe-9Cr-1Mo. Such connections are typically found in sodium fast reactors assemblies between wrapper tubes and assembly spikes. The objective is to understand the metallurgical features related to the assembly of these two steels and to evaluate the possibilities of using powder metallurgy and additive manufacturing to produce austenitic/martensitic steel transitions. With this work, the ability of additive manufacturing and powder metallurgy to overcome this challenge, by producing chemically graded parts, is demonstrated. Beyond the replacement of already existing parts, the possibilities opened by the additive manufacturing of gradient materials are very varied. It also constitutes a new tool at the disposal of design offices to imagine new designs and applications. This study demonstrates the potential presented by these gradient materials for future innovations.