Comparative study of sinterability and thermal stability in plasma-sintered niobium and vanadium beryllides

Kim, Jae-Hwan; Nakamichi, Masaru

Niobium and vanadium-beryllium intermetallic compounds (beryllides) were synthesized by plasma sintering under different sintering times at 1273 K. The beryllide with 7.7 at.% Nb mainly consisted of various phases of Be, BeNb, BeNb, and BeNb, whereas that with 7.7 at.% V consisted of BeV, BeV, and V. As the sintering time increased, area fractions of the target compositions BeNb and BeV increased while that of Be decreased. A comparative analysis demonstrated that the beryllide with 7.7 at.% Nb a showed higher density as well as a greater hardness than that with 7.7 at.% V, due to there being less difference between the sintering temperature and the melting point. In terms of thermal phase stability, the beryllide with 7.7 at.% Nb showed good thermal phase stability with fewer pores and a smaller unhomogenized area, because the beryllide contained a smaller area fraction of the Be phase, which may cause evaporation resulting in pore formation.