Microstructural and tritium release examination of titanium beryllides

Microstructural examinations of Be–Ti specimens supplied by Company Goraieb Versuchstechnik (GVT) and Brush Wellman Inc. (BW), and also pure beryllium samples of S-65H grade from BW were carried out by means of optical metallography and Transmission Electron Microscopy (TEM). It was established that the structure of Be12Ti, BW, has only a single-phase which is Be12Ti with a tetragonal lattice. The structure of Be–Ti samples from GVT, contains Be12Ti with a tetragonal lattice and beryllium with hexagonal close-packed (HCP) lattice. In S-65H grade particles of beryllium oxide BeO having a hexagonal form, located, mainly, on grain boundaries, were found. Tritium release examinations of the same beryllium materials after preliminary high temperature loading with H2 – 500 аррm T2 gas mixture were carried out. Be12Ti, BW, has a maximal ability to release tritium at a heating with a permanent rate up to 1373 K, S-65H has a minimal ability, Be–Ti, GVT, has an intermediate value. It can be explained by a higher diffusion mobility of hydrogen isotopes in a tetragonal lattice of Be12Ti compared to HCP lattice of pure beryllium.