TY - JOUR
T1 - Integrally directionally solidified microstructure of an niobium silicide based ultrahigh temperature alloy
AU - Guo, Xiping
AU - Guo, Haisheng
AU - Guan, Chengfang Yao Ping
PY - 2009/3/20
Y1 - 2009/3/20
N2 - Integrally directional solidification of an advanced Nb silicide based ultrahigh temperature alloy was conducted with the use of special ceramic crucibles. The melt temperature was 2000°C and the withdrawing rate was respectively 5, 10, 15, 30, 50, 80 and 100 μm/s. The directionally solidified microstructure was composed of primary (Nb,X)5Si3 rods and (Nb,Ti)ss + (Nb,X)5Si3 eutectic colonies (here X represents Ti and Hf elements) that distributed evenly and aligned erectly along the growth direction. The quenched solid/liquid (S/L) interfaces had the morphology of a series of protruded parallel eutectic cells along the growth direction. (Nb,Ti)ss and (Nb,X)5Si3 slices grew in a coupled manner in each eutectic cell, forming a typical lamellar eutectic morphology. Both the average diameter of eutectic cells and lamellar spacing in them decreased with the increase of withdrawing rates. The solidification path was that primary (Nb,X)5Si3 rods formed firstly and then the retained liquid around solidified into (Nb,Ti)ss + (Nb,X)5Si 3 eutectic cells.
AB - Integrally directional solidification of an advanced Nb silicide based ultrahigh temperature alloy was conducted with the use of special ceramic crucibles. The melt temperature was 2000°C and the withdrawing rate was respectively 5, 10, 15, 30, 50, 80 and 100 μm/s. The directionally solidified microstructure was composed of primary (Nb,X)5Si3 rods and (Nb,Ti)ss + (Nb,X)5Si3 eutectic colonies (here X represents Ti and Hf elements) that distributed evenly and aligned erectly along the growth direction. The quenched solid/liquid (S/L) interfaces had the morphology of a series of protruded parallel eutectic cells along the growth direction. (Nb,Ti)ss and (Nb,X)5Si3 slices grew in a coupled manner in each eutectic cell, forming a typical lamellar eutectic morphology. Both the average diameter of eutectic cells and lamellar spacing in them decreased with the increase of withdrawing rates. The solidification path was that primary (Nb,X)5Si3 rods formed firstly and then the retained liquid around solidified into (Nb,Ti)ss + (Nb,X)5Si 3 eutectic cells.
KW - Nb silicide based alloy
KW - S/L interface.
KW - eutectic
KW - integrally directional solidification
UR - http://www.scopus.com/inward/record.url?scp=66749171164&partnerID=8YFLogxK
U2 - 10.1142/s0217979209060518
DO - 10.1142/s0217979209060518
M3 - 文章
AN - SCOPUS:66749171164
SN - 0217-9792
VL - 23
SP - 1093
EP - 1098
JO - International Journal of Modern Physics B
JF - International Journal of Modern Physics B
IS - 6-7
ER -