TY - JOUR
T1 - Liquid-solid phase equilibria in Nb-rich corner of the Nb-Ti-Si-B system
AU - Sun, Zhiping
AU - Guo, Xiping
AU - Zhang, Chuan
PY - 2012/5/5
Y1 - 2012/5/5
N2 - Nb-Ti-Si based alloys are considered as candidates of next-generation high temperature materials (i.e., working temperature >1200°C). Boron has a beneficial effect in enhancing the oxidation resistance and reducing the anisotropy ratio a c/a a of the T2 phase in the Nb-Si alloys. The liquid-solid multiphase equilibria in the Nb-Ti-Si alloys with B additions have been investigated via an approach of integrating thermodynamic modeling with designed experiments. The present study suggests that Ti and Si additions increase the stability of Nb 3B 2, and the primary region of Nb 3B 2 will appear in the Nb-Ti-Si-B quaternary, while there is no primary solidification region of Nb 3B 2 in the constitute binaries and ternaries. The proposed liquidus surface of the Nb-rich Nb-Ti-Si-B system is associated with eight primary solidification regions of Nbss, T2, T1, D8 8, (Nb,Ti) 3Si, NbB, TiB and Nb 3B 2. The direct eutectic solidification occurs between Nbss and T2 in the Nb-rich region in the Nb-Ti-Si-B liquidus projection, which could provide new opportunities for alloy design based on the Nb-Ti-Si-B system.
AB - Nb-Ti-Si based alloys are considered as candidates of next-generation high temperature materials (i.e., working temperature >1200°C). Boron has a beneficial effect in enhancing the oxidation resistance and reducing the anisotropy ratio a c/a a of the T2 phase in the Nb-Si alloys. The liquid-solid multiphase equilibria in the Nb-Ti-Si alloys with B additions have been investigated via an approach of integrating thermodynamic modeling with designed experiments. The present study suggests that Ti and Si additions increase the stability of Nb 3B 2, and the primary region of Nb 3B 2 will appear in the Nb-Ti-Si-B quaternary, while there is no primary solidification region of Nb 3B 2 in the constitute binaries and ternaries. The proposed liquidus surface of the Nb-rich Nb-Ti-Si-B system is associated with eight primary solidification regions of Nbss, T2, T1, D8 8, (Nb,Ti) 3Si, NbB, TiB and Nb 3B 2. The direct eutectic solidification occurs between Nbss and T2 in the Nb-rich region in the Nb-Ti-Si-B liquidus projection, which could provide new opportunities for alloy design based on the Nb-Ti-Si-B system.
KW - High-temperature alloys
KW - Intermetallics
KW - Liquid-solid reactions
KW - Microstructure
KW - Phase diagrams
UR - http://www.scopus.com/inward/record.url?scp=84862799402&partnerID=8YFLogxK
U2 - 10.1016/j.jallcom.2012.01.142
DO - 10.1016/j.jallcom.2012.01.142
M3 - 文章
AN - SCOPUS:84862799402
SN - 0925-8388
VL - 522
SP - 149
EP - 156
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
ER -