TY - JOUR
T1 - Phase transformation in Ti-48Al-6Nb porous alloys and its influence on pore properties
AU - Wang, Fan
AU - Liang, Yongfeng
AU - Shang, Shunli
AU - Liu, Zi Kui
AU - Lin, Junpin
N1 - Funding Information:
This research was supported by the National Natural Science Foundation of China (No. 51271016 ), the Beijing Natural Science Foundation (No. 2122043 ) and the National Basic Research Program of China (973 Program, No. 2011CB605500 ).
Publisher Copyright:
© 2015 Elsevier Ltd.
PY - 2015/10/15
Y1 - 2015/10/15
N2 - Ti-48Al-6Nb porous alloys were synthesized by the powder metallurgy (PM) method, and the associated phase transformation and pore parameter were investigated in order to reveal the pore-formation mechanism. The present results indicate that the Nb-Al and Ti-Al phase transformations contribute to the pore-formation. It was found that the five-step phase transformations for the Ti-48Al-6Nb porous alloys occur as follows: (1) Ti+Al→TiAl3 at 600-700°C; (2) Nb+Al→NbAl3 at 700-900°C; (3) TiAl3+Ti→TiAl at 900-1100°C; (4) TiAl+Ti→Ti3Al/TiAl at 1100-1350°C; (5) NbAl3+Nb→Nb2Al and the Ti3Al turns to the major phase at 1350°C. These phase transformations made the pore-diameter increasing continuously from 1.71μm to 12.10μm and also made the pore volume distributing widely. At the second step of 700-900°C, the Nb-Al phase transformation leads to 5% more volume expansion compared to the Ti-Al based porous alloys. Meanwhile, the porosity and total pore area initially increase and then decrease at this step, but they increase intensely at the final step, which is needed as a catalytic carrier.
AB - Ti-48Al-6Nb porous alloys were synthesized by the powder metallurgy (PM) method, and the associated phase transformation and pore parameter were investigated in order to reveal the pore-formation mechanism. The present results indicate that the Nb-Al and Ti-Al phase transformations contribute to the pore-formation. It was found that the five-step phase transformations for the Ti-48Al-6Nb porous alloys occur as follows: (1) Ti+Al→TiAl3 at 600-700°C; (2) Nb+Al→NbAl3 at 700-900°C; (3) TiAl3+Ti→TiAl at 900-1100°C; (4) TiAl+Ti→Ti3Al/TiAl at 1100-1350°C; (5) NbAl3+Nb→Nb2Al and the Ti3Al turns to the major phase at 1350°C. These phase transformations made the pore-diameter increasing continuously from 1.71μm to 12.10μm and also made the pore volume distributing widely. At the second step of 700-900°C, the Nb-Al phase transformation leads to 5% more volume expansion compared to the Ti-Al based porous alloys. Meanwhile, the porosity and total pore area initially increase and then decrease at this step, but they increase intensely at the final step, which is needed as a catalytic carrier.
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U2 - 10.1016/j.matdes.2015.05.072
DO - 10.1016/j.matdes.2015.05.072
M3 - Article
AN - SCOPUS:84941270242
SN - 0264-1275
VL - 83
SP - 508
EP - 513
JO - Materials and Design
JF - Materials and Design
ER -