Synthesis of Be12Ti compound via arc melting or hot isostatic pressing

According to the recently proposed changes of the HCPB design concept of tritium breeding blanket for the DEMO fusion reactor, massive Be12Ti blocks are considered to be used for neutron multiplication. The paper compares two possible fabrication routes of solid beryllide blocks: combination of hot extrusion with arc melting or with hot isostatic pressing (HIP). Be-Ti composite rods produced by powder extrusion were chosen as a starting material. After arc melting, the ingot had cellular microstructure revealing mixture of Be12Ti and Be10Ti phases with considerable porosity. The powder metallurgy route, including extrusion and HIP, allows to achieve 98.6% of theoretical density and fine-grained Be12Ti microstructure with small amount of residual Be phase. EBSD analysis together with TEM showed that titanium beryllide has a grain size of 0.3-2.5 mm. It was observed that fine BeO particles are distributed along the grain boundaries and can pin them. Titanium beryllide after HIP has high microhardness of 1420 HV and fracture toughness of about 2.4 MPam(1/2) comparable with that of many ceramics. The advantages of Be12Ti blocks manufacturing using extrusion and HIP are discussed. (C) 2019 Elsevier B.V. All rights reserved.