The effect of zirconium on the Ti-(42-46 at.%)Al system

Autor: Michael Musi, Stefan Kardos, Lukas Hatzenbichler, David Holec, Andreas Stark, Melissa Allen, Volker Güther, Helmut Clemens, Petra Spoerk-Erdely
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Acta materialia 241, 118414 (2022). doi:10.1016/j.actamat.2022.118414
Musi, M.; Kardos, S.; Hatzenbichler, L.; Holec, D.; Stark, A.; Allen, M.; Güther, V.; Clemens, H.; Spoerk-Erdely, P.: The effect of zirconium on the Ti-(42-46 at.%)Al system. In: Acta Materialia. Vol. 241 (2022) 118414. (DOI: /10.1016/j.actamat.2022.118414)
ISSN: 1359-6454
Popis: Acta materialia 241, 118414 (2022). doi:10.1016/j.actamat.2022.118414
In recent years, Zr has emerged as a promising alloying element for intermetallic γ-TiAl based alloys to improve their mechanical properties. The present work focuses on the influence of this element on the microstructure and the thermodynamic phase equilibria in the ternary Ti-(42-46)Al-(2-4)Zr (at.%) system. Alloying with Zr was found to increase the amount of the γphase in the microstructure of cast material densified by hot-isostatic pressing. Simultaneously, the material’s hardness increased due to solid solu- tion strengthening as well as the refinement of lamellae in the α2 / γcolonies. With respect to the phase transformation behaviour, a significant decrease of the solidus temperature was observed in the high Zr alloyed material variants. In combination with the stabilization of the γphase, this essentially results in a narrowing of the single αphase field region in the Ti-Al-Zr phase diagram derived in this work. In situ high-energy X-ray diffraction was performed on Ti-46Al-2Zr and Ti-46Al-4Zr (at.%) specimens to investigate the phase transitions above and below the solidus temperature by utilizing two different ex- perimental setups. These experiments showed that upon heating, small amounts of βphase are formed in both alloys prior to the transition into the peritectic α+ β+ L phase field region. Furthermore, an ad- ditional heat treatment study was conducted to determine the influence of Zr and temperature on the resulting microstructure. The combination of X-ray diffraction techniques with ab-initio calculations re- vealed a significant asymmetric influence of Zr on the lattice parameter of the γphase, resulting in a decreasing c/a ratio.
Published by Elsevier Science, Amsterdam [u.a.]
Databáze: OpenAIRE
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