TY - JOUR
T1 - Microstructure of Nb-Ti-Cr-Si based ultrahigh temperature alloy processed by integrally directional solidification
AU - Guo, B. H.
AU - Guo, X. P.
N1 - Publisher Copyright:
© 2015 Institute of Materials, Minerals and Mining
PY - 2015/1/1
Y1 - 2015/1/1
N2 - The Nb-Ti-Cr-Si based ultrahigh temperature alloy was integrally directionally solidified with the using of special ceramic crucibles. The effects of different withdrawing rates on the microstructure and the solidification path in a Nb-Ti-Cr-Si based ultrahigh temperature alloy were investigated. The results showed that the microstructure was composed of primary niobium solid solution (Nbss) dendrites, Nbss/(Nb,X)5Si3 (here X represents Ti and Hf elements) eutectic colonies and fine Ti rich phase layer between Nbss dendrites and Nbss/(Nb,X)5Si3 eutectic colonies when the withdrawal rates vary from 2·5 to 10 μm s-1. However, the directionally solidified microstructures were composed of primary Nbss dendrites, Nbss/(Nb,X)5Si3 eutectic colonies and finer (Ti,Nb)ss/Nb3Si/Cr2Nb colonies colonies when the withdrawal rate was reached and exceed than 20 μm s-1. The primary Nbss and Nbss/(Nb,X)5Si3 eutectic aligned the growth direction when the withdrawal rates vary from 2·5 to 20 μm s-1; however, the discontinuous (Nb,X)5Si3 plates were present when the withdrawal rates vary from 50 to 100 μm s-1. The solidification path was studied according to the microstructure of solid/liquid interface.
AB - The Nb-Ti-Cr-Si based ultrahigh temperature alloy was integrally directionally solidified with the using of special ceramic crucibles. The effects of different withdrawing rates on the microstructure and the solidification path in a Nb-Ti-Cr-Si based ultrahigh temperature alloy were investigated. The results showed that the microstructure was composed of primary niobium solid solution (Nbss) dendrites, Nbss/(Nb,X)5Si3 (here X represents Ti and Hf elements) eutectic colonies and fine Ti rich phase layer between Nbss dendrites and Nbss/(Nb,X)5Si3 eutectic colonies when the withdrawal rates vary from 2·5 to 10 μm s-1. However, the directionally solidified microstructures were composed of primary Nbss dendrites, Nbss/(Nb,X)5Si3 eutectic colonies and finer (Ti,Nb)ss/Nb3Si/Cr2Nb colonies colonies when the withdrawal rate was reached and exceed than 20 μm s-1. The primary Nbss and Nbss/(Nb,X)5Si3 eutectic aligned the growth direction when the withdrawal rates vary from 2·5 to 20 μm s-1; however, the discontinuous (Nb,X)5Si3 plates were present when the withdrawal rates vary from 50 to 100 μm s-1. The solidification path was studied according to the microstructure of solid/liquid interface.
KW - Eutectic colonies
KW - Integrally directional solidification
KW - Nb-Ti-Cr-Si based ultrahigh temperature alloy
KW - Solid/liquid interface
UR - http://www.scopus.com/inward/record.url?scp=84919491619&partnerID=8YFLogxK
U2 - 10.1179/1743284714Y.0000000511
DO - 10.1179/1743284714Y.0000000511
M3 - 文章
AN - SCOPUS:84919491619
SN - 0267-0836
VL - 31
SP - 231
EP - 236
JO - Materials Science and Technology
JF - Materials Science and Technology
IS - 2
ER -