Abstract
Alloy 4822 (Ti-48Al-2Cr-2Nb at. pct) cast material was given a controlled heat treatment cycle to generate a casting nearly lamellar (CNL) microstructure that enhances the temperature capability over its current engineering casting duplex (CDP) microstructure form. The cycle consisted of three steps: a short α field annealing, an α + γ field annealing, and then aging at a low temperature, with each step being followed by controlled cooling. The resulted microstructure is shown to be a mixture of non-uniformly distributed ~ 250 μm size lamellar colonies containing ~ 0.15 µm spaced laths. Standard tensile testing at 700 °C shows a yield stress of 344 MPa that is ~ 55 MPa greater than that of the current engineering CDP form. The sequential microstructure evolution processes following the three-step thermal cycle are assessed and explained in terms of phase transformations taking place across and below the α transus upon isothermal treatment and subsequent cooling. The resulted increases in high-temperature strengthening are explained by the colony and γ grain size distributions. The strengthening mechanism along with the significance is discussed.
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Y.W. Kim: JOM, 1994, vol. 46, pp. 30-49.
H. Clemens and H. Kestler: Adv. Eng. Mater., 2000, vol. 2, pp. 551-70.
Y-W. Kim and S.L. Kim: JOM, 2018, vol. 70, pp. 553-60.
C. Austin and T. Kelly: Structural Intermetallics, 1993, TMS, pp. 143–50.
B. London, D. Larsen, D.A. Wheeler, and P.R. Aimone: Structural Intermetallics, 1993, TMS, pp. 151–57.
F. Appel, J.D.H. Paul, M. Oehring, C. Buque, C. Klinkenberg, and T. Carneiro: Niobium for High Temperature Applications, 2004, TMS, pp. 139–52.
H. Clemens, H.F. Chladil, W. Wallgram, G.A. Zickler, R. Gerling, K.-D. Liss, S. Kremmer, V. Güther, and W. Smarsl: Intermetallics, 2008, vol. 16, pp. 827-33.
G.L. Chen, W.J. Zhang, Z.C. Liu, S.J. Li, and Y-W. Kim: Gamma Titanium Aluminides 1999, 1999, TMS, pp. 371–80.
M.J. Weimer and T.J. Kelly: GE Aviation, Ohio, Unpublished Results Presented at 3rd int’l Workshop on Gamma TiAl Technologies, 2006.
B.P. Bewlay, M. Weimer, T. Kelly, A. Suzuki, and P.R. Subramanian: Intermetallic-Based Alloys-Science, Technology, and Applications, Mater. Res. Soc. Symp. Proc., Warrendale, PA, 2012, vol. 1516, pp. 49–58.
W. Smarsly, J. Esslinger, and H. Clemens: MTU, Germany, research and development results presented at GTA-2014, 2014.
Habel U, Heutling F, Helm D, Kunze C, Smarsly W, Das G, Clemens H: World Titanium. Wiley, Hoboken, pp. 1223-27 (2015)
Y-W. Kim and D.M. Dimiduk: JOM, 1991, vol. 41, pp. 40-47.
Y-W. Kim, Acta Metall. Mater. 1992, vol. 40, pp. 1121-34.
X.J. Xu, Y.L. Wang, F.Z. Gao, and G.L. Chen: J. alloys compd., 2006, vol. 414, pp. 131-36.
X.J. Xu, J.P. Lin, Z.K. Teng, Y.L. Wang, and G.L. Chen: Mater. Lett., 2007, vol. 61, pp. 369-73.
G. Yang, H.C. Kou, Y. Liu, J.R. Yang, J. Wang, S.Y. Zhang, J.S. Li, and H.Z. Fu: Intermetallics, 2015, vol. 63, pp. 1-6.
Y.W. Kim: JOM, 1989, vol. 41, pp. 24-30.
B.D. Worth, J.W. Jones, and J.E. Allison: Metall. Mater. Trans. A, 1995, vol. 264, pp. 2947-59.
Y.W. Kim, Mater. Sci. Eng. A, 1995, vol. A192/193, pp. 519-533.
Y.W. Kim: Intermetallics, 1998, vol. 6, pp. 623-28.
J.C. Schuster and M.Palm: J. Phase Equilib. Diff., 2006, vol. 27, pp. 255–77.
U.R. Kattner, J.C. Lin, and Y.A. Chang: Metall. Mater. Trans. A, 1992, vol. 23, pp. 2081-90.
Y.L. Jung and J.K. Park: Acta Mater., 1998, vol. 46, pp. 4123-30.
M.J. Blackburn: The Science Technology & Application of Titanium, Pergamon Press, Oxford, United Kindom, 1970, pp. 633-43.
A. Denquin and S. Naka: Acta Mater., 1996, vol. 44, pp. 343-52.
S.A. Jones and M.J. Kafuman: Acta Metall. Mater., 1993, vol. 41, pp. 387-98.
M. Charpentier, A. Hazotte, and D. Daloz: Mater. Sci. Eng. A, 2008, vol. 491, pp. 321-30.
Z.W. Huang: Scr. Mater., 2005, vol. 52, pp. 1021-25.
Y.W. Cui, G.L. Xu, R. Kato, X.G. Lu, R. Kainuma, and K. Ishida: Metall. Mater. Trans. A, 2013, vol. 44A, pp. 1621–25.
M. Koppers, C. Herzig, M. Friesel, and Y. Mishin: Acta. Mater., 1997, vol. 45, pp. 4181-91.
C.M. Sellars and J. A. Whiteman: Metal Sci., 1978, vol. 13, pp. 187-94.
S.F. Franzén and J. Karlsson: Master’s Thesis, Chalmers University of Technology, Gothenburg, Sweden, 2010.
J.H. Moll: JOM, 2000, vol. 52, 32-34.
H. Clemens and S. Mayer: Adv. Eng. Mater., 2013, vol. 15, pp. 191-215.
Y. Xia, P. Yu, G.B. Schaffer, and M. Qian: Mater. Sci. Eng. A, 2013, vol. 574, pp. 176-85.
Q. Wang, R. Chen, X. Gong, J. Guo, Y. Su, H. Ding, and H. Fu: Metall. Mater. Trans. A, 2018, vol. 49A, pp. 4555–64.
S. Biamino, A. Penna, U. Ackelid, S. Sabbadini, O. Tassa, P. Fino, M. Pavese, P. Gennaro, and C. Badini: Intermetallics, 2011, vol. 19, pp. 776-81.
D. Hu: Intermetallics, 2001, vol. 9, pp. 1037-43.
X.H. Wu: Intermetallics, 2006, vol. 14, pp. 1114-22.
Acknowledgments
The current study was financially supported by the National Natural Science Foundation of China (Nos. 51401168 and 51774238) and the 2018 Joint Foundation of Ministry of Education for Equipment Pre-research (No. 6141A020332).
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Gao, Z., Yang, J., Wu, Y. et al. A Newly Generated Nearly Lamellar Microstructure in Cast Ti-48Al-2Nb-2Cr Alloy for High-Temperature Strengthening. Metall Mater Trans A 50, 5839–5852 (2019). https://doi.org/10.1007/s11661-019-05491-8
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DOI: https://doi.org/10.1007/s11661-019-05491-8