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

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, Be12Nb, Be17Nb2, and Be2Nb, whereas that with 7.7 at.% V consisted of Be12V, Be2V, and V. As the sintering time increased, area fractions of the target compositions Be12Nb and Be12V 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.