Phase relation and transition in the Ti-Al-Mn system

Seeking and optimizing beta solidified gamma (BSG) TiAl alloys have been recognized as hot research topics in recent few decades. Knowledge on phase equilibrium information including solubility limit and stability range can contribute to a necessary basis for tuning the performance of BSG alloys. In...

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Published inJournal of alloys and compounds Vol. 861; p. 158578
Main Authors Huang, X.M., Cai, G.M., Zhang, J., Zheng, F., Liu, H.S., Jin, Z.P.
Format Journal Article
LanguageEnglish
Published Elsevier B.V 25.04.2021
Subjects
Microstructure
Phase equilibria
Phase transformation
Ti-Al-Mn system
Phase equilibria
Phase transformation
Ti-Al-Mn system
Microstructure
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Summary:Seeking and optimizing beta solidified gamma (BSG) TiAl alloys have been recognized as hot research topics in recent few decades. Knowledge on phase equilibrium information including solubility limit and stability range can contribute to a necessary basis for tuning the performance of BSG alloys. In this work, we investigated phase relation and transformation in the Ti-Al-Mn system from 973 to 1373 K. With the increase of temperature, the β(Ti) phase region extends continuously accompanied by the change of Al solubility from 9.0 at% at 973 K to 34.7 at% at 1373 K. TiAl shows a wide composition range with the solubility of Mn increasing slightly along the temperature. A ternary Heusler phase β1 (Ti2AlMn) is confirmed to be stable below 1110.5 ± 12.5 K. And B2 phase with an island-like region exists in the temperature range of 1098–1123 K and can connect with Al-rich β(Ti) to form a whole as the temperature increases. According to the evolution of phase relations, two peritectoid reactions B2 + TiAl → Ti3Al + TiMn2 (1160.5 ± 12.5 K) and TiMn1−x + TiMn2 → Ti3Al + TiMn1+x (973–1023 K) can be defined. In addition, it was found that TiMn1−x can be stable up to 1373 K. [Display omitted] •Phase relation and transition in the Ti-Al-Mn system were determined entirely.•Island-like ordered B2 phase starts to occur at a temperature of 1073–1098 K.•The ternary phase β1 (~ Ti2AlMn) has been observed below 1110.5 ± 12.5 K.•The reaction B2 + TiAl → Ti3Al + TiMn2 happens at 1160.5 ± 12.5 K.•Binary phase TiMn1−x is found stable at both 1273 and 1373 K.
ISSN:0925-8388
1873-4669
DOI:10.1016/j.jallcom.2020.158578