TY - JOUR
T1 - Understanding the role of carbon atoms on microstructure and phase transformation of high Nb containing TiAl alloys
AU - Wu, Zeen
AU - Hu, Rui
AU - Zhang, Tiebang
AU - Zhang, Fan
AU - Kou, Hongchao
AU - Li, Jinshan
N1 - Publisher Copyright:
© 2016 Elsevier Inc.
PY - 2017/2/1
Y1 - 2017/2/1
N2 - The microstructure and solidification behavior of high Nb containing TiAl alloys with the composition of Ti-46Al-8Nb-xC (x = 0.1, 0.7, 1.4, 2.5 at.%) prepared by arc-melting method have been investigated in this work. The results give evidence that the addition of carbon changes the solidification behavior from solidification via the β phase to the peritectic solidification. And carbon in solid solution enriches in the α2 phase and increases the microhardness. As the carbon content increases to 1.4 at.%, plate-shape morphology carbides Ti2AlC (H phase) precipitate from the TiAl matrix which leads to the refinement microstructure. By aging at 1173 K for 24 h after quenching treatment, fine needle-like and granular shape Ti3AlC (P phase) carbides are observed in the matrix of Ti-46Al-8Nb-2.5C alloy, which distribute along the lamellar structure or around the plate-shape Ti2AlC. Transmission electron microscope observation shows that the Ti3AlC carbides precipitate at dislocations. The phase transformation in-situ observations indicate that the Ti2AlC carbides partly precipitate during the solid state phase transformation process.
AB - The microstructure and solidification behavior of high Nb containing TiAl alloys with the composition of Ti-46Al-8Nb-xC (x = 0.1, 0.7, 1.4, 2.5 at.%) prepared by arc-melting method have been investigated in this work. The results give evidence that the addition of carbon changes the solidification behavior from solidification via the β phase to the peritectic solidification. And carbon in solid solution enriches in the α2 phase and increases the microhardness. As the carbon content increases to 1.4 at.%, plate-shape morphology carbides Ti2AlC (H phase) precipitate from the TiAl matrix which leads to the refinement microstructure. By aging at 1173 K for 24 h after quenching treatment, fine needle-like and granular shape Ti3AlC (P phase) carbides are observed in the matrix of Ti-46Al-8Nb-2.5C alloy, which distribute along the lamellar structure or around the plate-shape Ti2AlC. Transmission electron microscope observation shows that the Ti3AlC carbides precipitate at dislocations. The phase transformation in-situ observations indicate that the Ti2AlC carbides partly precipitate during the solid state phase transformation process.
KW - Interstitial content
KW - Microstructure
KW - Phase transformation
KW - Precipitates
KW - Solidification behavior
KW - TiAl
UR - http://www.scopus.com/inward/record.url?scp=85006325031&partnerID=8YFLogxK
U2 - 10.1016/j.matchar.2016.12.008
DO - 10.1016/j.matchar.2016.12.008
M3 - 文章
AN - SCOPUS:85006325031
SN - 1044-5803
VL - 124
SP - 1
EP - 7
JO - Materials Characterization
JF - Materials Characterization
ER -