Microstructure and high-temperature mechanical performance of industrial-scale titanium and chromium beryllides for fusion applications

The development of materials for the breeding blanket of future fusion devices requires a combination of high-temperature strength, radiation resistance, and compatibility with other materials. While beryllides have long been considered as neutron multipliers due to their favorable nuclear properties, their potential structural role has remained largely overlooked. These materials form an exotic class of beryllium-based intermetallics that may offer advantages in both neutronics and mechanical performance. We report the first comprehensive microstructural and mechanical characterization of full-scale TiBe$_{12}$ and CrBe$_{12}$ blocks fabricated by industrial vacuum hot pressing. TiBe$_{12}$ shows a fine-grained (≈7 μm) structure with ≈ 7 % free beryllium and frequent twin boundaries, while CrBe$_{12}$ has coarser grains (≈40 μm) and < 2 % beryllium. Both compounds exhibit high microhardness (>1000 HV) and strong room-temperature compressive strength (2030 MPa for TiBe$_{12}$; 1750 MPa for CrBe$_{12}$). Nanoindentation confirmed hardness values of 13.6–14.5 GPa and elastic moduli of 285 GPa
(TiBe$_{12}$) and 304 GPa (CrBe$_{12}$). ... mehrThey retain strength at 1000◦C (740 MPa and 460 MPa, respectively) and develop ductility above 850◦C, with up to 20 % deformation at 1200◦C. In three-point bending, TiBe$_{12}$ reaches 540 MPa at 800◦C, outperforming CrBe$_{12}$ and many other materials. The results are compared with available data on NbBe$_{12}$ and Ta2Be17, as well as with conventional high-temperature materials. Given that only very limited mechanical information exists for beryllides, this study substantially expands the database for this exotic class of compounds. In particular, the identification of twinning in TiBe$_{12}$ and the detailed comparison of strength, hardness, and elastic moduli provide new insights into their deformation behavior. Overall, the findings highlight the potential of TiBe$_{12}$ and CrBe$_{12}$ to bridge functional and structural roles, supporting their application not only in fusion blankets but also in aerospace, fission, and other extreme environments.