Nb-T2 합금의 파쇄분말을 사용한 Nb-Si-B계 합금의 제조

Abstract

Nb-Si-B alloys with Nb-rich compositions are fabricated by spark plasma sintering for high-temperature structural applications. Three compositions are selected: 75 at% Nb (Nb0.7), 82 at% Nb (Nb1.5), and 88 at% Nb (Nb3), the atomic ratio of Si to B being 2. The microstructures of the prepared alloys are composed of Nb and T2 phases. The T2 phase is an intermetallic compound with a stoichiometry of Nb5Si3-xBx (0 ≤ x ≤ 2). In some previous studies, Nb-Si-B alloys have been prepared by spark plasma sintering (SPS) using Nb and T2 powders (SPS 1). In the present work, the same alloys are prepared by the SPS process (SPS 2) using Nb powders and hypereutectic alloy powders with composition 67at%Nb-22at%Si-11at%B (Nb67). The Nb67 alloy powders comprise T2 and eutectic (T2 + Nb) phases. The microstructures and hardness of the samples prepared in the present work have been compared with those previously reported; the samples prepared in this study exhibit finer and more uniform microstructures and higher hardness.