Effect of grain size on the sinterability and reactivity of vanadium-beryllium intermetallic compounds

Vanadium beryllium intermetallic compounds (Be12V beryllides) are attractive materials for refractory and fusion applications at high temperatures. In this study, to investigate the effect of grain size on sinterability and reactivity of beryllides at high temperatures (expecting operation temperatures), single-phase vanadium beryllides with different grain sizes were fabricated via pulverization of homogenized powders and plasma sintering. While evaluating sintered Be12V, as the ball-milling time increased, the powder size decreased. As this grain size deceased, density and hardness increased. With respect to thermal expansion, the coefficient of thermal expansion slightly increased with decreasing grain size. As results of reactivity and the scanning electron microscopic observations, it indicated that grain boundary oxidation is predominant at 1273 K, whereas inter- granular oxidation prevails at 1473 K. Accordingly, as the grain size increased up to 10 mu m the weight gain and the H-2 generation amount decreased at 1273 K and 1473 K, respectively.