Microstructure evolution and enhanced creep property of a high Nb containing TiAl alloy with carbon addition

JOURNAL OF ALLOYS AND COMPOUNDS

卷:807

Article

Song, Lin^1,2  Hu, Xingguo¹  Wang, Li²  Stark, Andreas²  Lazurenko, Dania³  Lorenz, Uwe²  Lin, Junpin⁴  Pyczak, Florian²  Zhang, Tiebang¹ 

[1] Northwestern Polytech Univ, State Key Lab Solidificat Proc, Xian 710072, Shaanxi, Peoples R China

[2] Helmholtz Zentrum Geesthacht, Inst Mat Res, Max Planck Str 1, D-21502 Geesthacht, Germany

[3] Novosibirsk State Tech Univ, Karl Marks Str 20, Novosibirsk 630073, Russia

[4] Univ Sci & Technol Beijing, State Key Lab Adv Met & Mat, Beijing 100083, Peoples R China

关键词: TiAl alloys;    Precipitation;    Phase transitions;    Creep properties;    Transmission electron microscopy;    TEM;    Synchrotron radiation;   

DOI  :  10.1016/j.jallcom.2019.151649

来源: Elsevier

【 摘 要 】

The microstructure evolution and carbide precipitation in a Ti-46Al-8Nb-0.7C alloy as well as its creep properties at intermediate temperatures are investigated by high-energy X-ray diffraction and electron microscopy. The alloy with a nearly fully lamellar microstructure exhibits excellent creep resistance, which could be attributed to the good microstructural stability and strengthening effects from both P- and H-carbides. It is also found that the creep parameters have different effects on the precipitation of the carbides. The overall volume fraction of the carbides shows a positive correlation with the creep temperature and time. However, the thermal stability of P-carbides in the gamma grain interior decreases at a higher creep temperature. The creep stress hardly affects the precipitation and morphology development of the P-carbides. On the contrary, a higher stress can promote the H-carbide formation at the gamma/alpha(2) interfaces via alpha(2) lath decomposition in lamellar colonies. (C) 2019 Elsevier B.V. All rights reserved.

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