Microstructure Characterization of Nb-Si-B alloys Prepared by Spark Plasma Sintering Process Kim, Sang-Hwan; Kim, Nam-Woo; Jeong, Young-Keun; Oh, Sung-Tag; Kim, Young Do; Lee, Seong; Suk, Myung Jin;
Microstructural examination of the Nb-Si-B alloys at Nb-rich compositions is performed. The Nb-rich corner of the Nb-Si-B system is favorable in that the constituent phases are Nb (ductile and tough phase with high melting temperature) and phase (very hard intermetallic compound with favorable oxidation resistance) which are good combination for high temperature structural materials. The samples containing compositions near Nb-rich corner of the Nb-Si-B ternary system are prepared by spark plasma sintering (SPS) process using and Nb powders. bulk phase is made in arc furnace by melting the Nb slug and the Si-B powder compact. The bulk phase was subsequently ball-milled to powders. SPS is performed at and , depending on the composition, under 30 MPa for 600s, to produce disc-shaped specimen with 15 mm in diameter and 3 mm high. Hardness tests (Rockwell A-scale and micro Vickers) are carried out to estimate the mechanical property.