Compression properties of beryllide pebbles at high temperatures

Abstract

DEMO (demonstration) fusion reactors require advanced neutron multipliers with low swelling and high stability at high temperatures. Research on beryllium intermetallic compounds (beryllides (Be12V)) has been conducted, and the authors have successfully fabricated Be12V and Be12Ti0.3V0.7 ternary pebbles, which are considerably stable at high temperatures. In this study, to evaluate the mechanical properties of these pebbles, compression tests for a single pebble were performed at room temperature and high temperatures of 600 and 800 K. Be12Ti0.3V0.7 pebbles exhibited a higher crush load than Be12V pebbles; Be12Ti0.3V0.7 pebbles comprised remarkably fine grains due to dual phases. Scanning electron microscopy images of the fractured area demonstrated that the Be12V pebbles had a relatively large fracture with sharp edges, whereas the Be12Ti0.3V0.7 pebbles included considerably small grains. There was no noticeable temperature dependence of the crush load. The fracture and tensile strengths of Be12V and Be12Ti0.3 V0.7 pebbles were evaluated.