Laser powder bed fusion of refractory metals: A new way to produce components and devices for nuclear physics.

Refractory metals are of great interest for many applications. For instance, they are used in aerospace and biomedical sectors and for nuclear physics purposes, especially nuclear fusion and particle acceleration devices. High melting points, high wear resistance, and good mechanical strength at high temperatures are some of the characterizing properties of such metals. The production of components made of refractory metals via conventional manufacturing routes and the high cost of raw material do not allow an easy management of these materials. Additive Manufacturing (AM) overcomes many issues found in the traditional production processes. Also, it allows producing objects with complex shapes, minimizing wastage. This study investigates the Laser Powder Bed Fusion (LPBF) of refractory metals. The influence of process parameters on the quality of AM parts is extensively assessed. Mechanical, thermal, and electrical tests are carried out to estimate the AM material properties. The characterization process aims at producing pure Mo and Ta ion source parts, appositely redesigned for assembly and for performance improvement, whereas pure Nb is characterized to produce SFR cavities.