Trial fabrication of Be12Ti electrode for pebble production by rotating electrode method

Be12Ti has been one of candidates for advanced neutron multipliers, due to its high melting points and good chemical stability. Although Be12Ti is too brittle to product pebbles for neutron multipliers with the rotating electrode method (REM), a preliminary production of the pebbles which was made of two phase material of α-beryllium (α-Be) and Be12Ti was successfully demonstrated with REM. In this study a trial fabrication of the Be-5at%Ti'' ingot (α-Be + Be12Ti) for the REM electrode was carried out with a vacuum casting process. Three kinds of refractory crucibles (MgO, CaO and BeO) were tested for the evaluation of durability to the melt of Be-5%Ti. The water-cooled copper mould was applied for the casting mold to assist a one-direction solidification. The appearance (crack(s), shrinkage, etc.), microstructure and chemical analysis of the ''Be-5at%Ti'' ingots were investigated. As for the results of the trial fabrication, it was made clear that BeO crucible is most useful for the melting of Be-5at%Ti. The ingot, which was a size of φ85 x h150 mm, had h40mm sound portion from the bottom. The microstructure of the ingots showed two phases (probably α-Be and Be12Ti). The chemical composition of the Ti in the ingot were 3.1 - 6.2at%. (author)