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Role of Interface Boundaries in the Deformation Behavior of TiAl Polysynthetically Twinned Crystal: In situ Transmission Electron Microscopy Deformation Study

Published online by Cambridge University Press:  01 July 2005

Sung G. Pyo  and
Nack J. Kim
Sung G. Pyo
Affiliation:
Logic Process Development, R&D Center, MagnaChip, Cheongju 361-725, Korea
Nack J. Kim*
Affiliation:
Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
*
a)Address all correspondence to this author. e-mail: njkim@postech.ac.kr
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Abstract

To understand the role of boundaries in the deformation behavior of TiAl, in situ straining experiments in transmission electron microscopy have been performed on thin foils of polysynthetically twinned (PST) crystal of Ti–49.3 at.% Al. The deformation behavior of PST TiAl is anisotropic, depending on the angle between the lamellar boundaries and the straining axes. For L-orientation, deformation twins and ordinary dislocations transmit across the true-twin (TT) boundaries but are reflected at the pseudo-twin (PT) and rotational order-fault (RO) boundaries. For transverse (T) orientation, deformation twins are transmitted across all TT, PT, and RO boundaries. For I-orientation, shear deformation occurs parallel to the lamellar boundaries. There is a transmission of deformation across the interphase (IP) boundary in longitudinal orientation, but deformation is blocked and reflected at the IP boundary in T-orientation. The role of the various types of boundaries in localized deformation behavior was evaluated by considering Schmid factors and geometric compatibility factors.

Keywords

Intermetallic alloysMechanical propertiesTransmission electron microscopy (TEM)
Type
Articles
Information
Journal of Materials Research , Volume 20 , Issue 7 , July 2005 , pp. 1888 - 1901
Copyright
Copyright © Materials Research Society 2005

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References

REFERENCES

1Kim, Y-W. and Dimiduk, D.M.: Progress in the understanding of gamma titanium aluminides. J. Metals 43, 40 (1991).Google Scholar
2Huang, S.C. and Hall, E.L.: The effects of Cr additions to binary TiAl-base alloys. Metall. Mater. Trans. A 22, 2619 (1991).CrossRefGoogle Scholar
3Tsujimoto, T. and Hashimoto, K. Structures and properties of TiAl-base alloys containing Mn, in High-Temperature Ordered Intermetallic Alloys III, edited by Liu, C.T., Taub, A.I., Stoloff, N.S., and Koch, C.C. (Mater. Res. Soc. Symp. Proc. 133, Pittsburgh, PA, 1989), p. 391.Google Scholar
4Hahn, Y.D. and Whang, S.H.: Deformation and its structure in L1o Ti-Al-Nb compound alloys in High-Temperature Ordered Intermetallic Alloys III, edited by Liu, C.T., Taub, A.I., Stoloff, N.S., and Koch, C.C. (Mater. Res. Soc. Symp. Proc. 133, Pittsburgh, PA, 1989) p. 385.Google Scholar
5Cerreta, E. and Mahajan, S.: Formation of deformation twins in TiAl. Acta Mater. 49, 3803 (2001).CrossRefGoogle Scholar
6Zhang, L.C., Wang, J.G., Chen, G.L. and Sauthoff, G.: Structural change of deformation twin boundaries in a heavily deformed g-TiAl-based alloy. Mater. Lett. 45, 320 (2000).CrossRefGoogle Scholar
7Bartels, A. and Uhlenhut, H.: Anisotropy of plastic flow in strongly textured γ-TiAl-based alloys. Intermetallics 6, 685 (1998).CrossRefGoogle Scholar
8Lebensohn, R., Uhlenhut, H., Hartig, C. and Mecking, H.: Plastic flow of γ-TiAl-based polysynthetically twinned crystals: Micromechanical modeling and experimental validation. Acta Mater. 46, 4701 (1998).CrossRefGoogle Scholar
9Yoo, M.H. and Fu, C.L.: Physical constants, deformation twinning, and microcracking of titanium aluminides. Metall. Mater. Trans. A 29, 49 (1998).CrossRefGoogle Scholar
10Lu, L. and Pope, D.P.: Slip and twinning in TiAl PST crystals. Mater. Sci. Eng., A. 239–240, 126 (1997).CrossRefGoogle Scholar
11Yasuda, H.Y., Nakano, T. and Umakoshi, Y.: Thermal stability of deformation substructure of cyclically deformed TiAl PST crystals. Intermetallics 4, 289 (1996).CrossRefGoogle Scholar
12Park, H.S., Nam, S.W., Kim, N.J. and Hwang, S.K.: Refinement of the lamellar structure in TiAl-based intermetallic compound by addition of carbon. Scripta Mater. 41, 1197 (1999).CrossRefGoogle Scholar
13Pyo, S.G., Oh, J.K., Yoo, M.S., Kim, N.J. and Yamaguchi, M.: Compositional dependence of the deformation behaviour of ultrahigh-purity Ti-Al alloys. Philos. Mag. 84, 3001 (2004).CrossRefGoogle Scholar
14Pyo, S.G., Choi, S.M., Yoo, M.S., Oh, J.K., Whang, S.K. and Kim, N.J.: Nucleation and growth of alpha phase in hot extruded Ti-46.6Al-2W-1.4W intermetallic alloy produced by hot extrusion of elemental powders. Mater. Sci. Eng., A 374, 160 (2004).CrossRefGoogle Scholar
15Inui, H., Oh, M.H., Nakamura, A. and Yamaguchi, M.: Room-temperature tensile deformation of polysynthetically twinned (PST) crystals of TiAl. Acta Metall. Mater. 40, 3095 (1992).CrossRefGoogle Scholar
16Appel, F., Beaven, P.A. and Wagner, R.: Deformation processes related to interfacial boundaries in two-phase γ-titanium aluminides. Acta Metall. Mater. 41, 1721 (1993).CrossRefGoogle Scholar
17Umakoshi, Y. and Nakano, T.: The role of ordered domains and slip mode of α2 phase in the plastic behaviour of TiAl crystals containing oriented lamellae. Acta Metall. Mater. 41, 1155 (1993).CrossRefGoogle Scholar
18Fujiwara, T., Nakamura, A., Hosomi, M., Nishitani, S.R., Shirai, Y. and Yamaguchi, M.: Deformation of polysynthetically twinned crystals of TiAl with a nearly stoichiometric composition. Philos. Mag. A 61, 591 (1990).CrossRefGoogle Scholar
19Inui, H., Oh, M.H., Nakamura, A. and Yamaguchi, M.: Ordered domains in TiAl coexisting with Ti3Al in the lamellar structure of Ti-rich TiAl compounds. Philos. Mag. A 66, 539 (1992).CrossRefGoogle Scholar
20Inui, H., Oh, M.H., Nakamura, A. and Yamaguchi, M.: Deformation structures in Ti-rich TiAl polysynthetically twinned crystals. Philos. Mag. A 66, 557 (1992).CrossRefGoogle Scholar
21Godfrey, A.: The role of the α2 phase in the transmission of slip in lamellar TiAl-based alloys. Philos. Mag. A 77, 287 (1998).CrossRefGoogle Scholar
22Kishida, K., Inui, H. and Yamaguchi, M.: Deformation of lamellar structure in TiAl-Ti3Al two-phase alloys. Philos. Mag. A 78, 1 (1998).CrossRefGoogle Scholar
23Paidar, V. and Yamaguchi, M.: Compatibility stresses in bicrystals of polysynthetically twined TiAl. Mater. Sci. Eng., A 319–321, 332 (2001).CrossRefGoogle Scholar
24Wiezorek, J.M.K., Zhang, X-D., Clark, W.A.T. and Fraser, H.L.: Activation of slip in lamellae of α2-Ti3Al in TiAl alloys. Philos. Mag. 78, 217 (1998).Google Scholar
25Luster, M.A. and Morris, M.A.: Compatibility of deformation in two-phase Ti-Al alloys: Dependence on microstructure and orientation relationships. Metall. Mater. Trans. A 26, 1745 (1995).CrossRefGoogle Scholar
26Wiezorek, J.M.K., Zhan, X.D., Mills, M.J. and Fraser, H.L.: On the role of lamellar interfaces on the strength and ductility of two-phase titanium-aluminum in High-Temperature Ordered Intermetallic Alloys VIII, edited by George, E.P., Mills, M.J. and Yamaguchi, M. (Mater. Res. Soc. Symp. Proc. 552, Warrendale, PA, 1999), p. KK.3.5.1.Google Scholar
27Yao, K-F., Xiao, J. and Zhang, J.: In-situ deformation of TiAl PST crystals in TEM. Intermetallics 8, 569 (2000).CrossRefGoogle Scholar
28Zghal, S., Coujou, A. and Couret, A.: Transmission of the deformation through γ-γ interfaces in a polysynthetically twinned TiAl alloy: I. Ordered domain interfaces (120° rotational). Philos. Mag. A 81, 345 (2001).CrossRefGoogle Scholar
29Zghal, S. and Couret, A.: Transmission of the deformation through γ-γ interfaces in a polysynthetically twinned TiAl alloy: II. Twin interfaces (120° rotational). Philos. Mag. A 81, 365 (2001).CrossRefGoogle Scholar
30Lu, Y.H., Zhang, Y.G., Qiao, L.J., Wang, Y-B., Chen, C.Q. and Chu, W.Y.: In-situ TEM study of fracture mechanism of polysynthetically twinned (PST) crystals of TiAl alloys. Mater. Sci. Eng., A 289, 91 (2000).CrossRefGoogle Scholar
31Park, C.G., Lee, C.S. and Chang, Y.W.: Mechanical Behavior of Materials-VI Vol. 4, (Pergamon Press, Oxford, U.K. 1991) p. 3.Google Scholar
32Sastry, S.M.L. and Lipsitt, H.A.: Fatigue deformation of TiAl base alloys. Metall. Trans. A 8, 299 (1977).CrossRefGoogle Scholar
33Lee, T.C., Robertson, I.M. and Birnbaum, H.K.: An in situ transmission electron microscope deformation study of the slip transfer mechanisms in metals. Metall. Trans. A. 21, 2437 (1990).CrossRefGoogle Scholar
34Shen, Z., Wahoner, R.H. and Clark, W.A.T.: Dislocation and grain boundary interactions in metals. Acta Metall. 36, 3231 (1988).CrossRefGoogle Scholar
35Sun, Y.Q., Hazzledine, P.M. and Christian, J.W.: Intersections of deformation twins in TiAl. I. Experimental observations. Philos. Mag. A 68, 471 (1993).CrossRefGoogle Scholar
36Sun, Y.Q., Hazzledine, P.M. and Christian, J.W.: Intersections of deformation twins in TiAl. II. Models and analyses. Philos. Mag. A 68, 495 (1993).CrossRefGoogle Scholar
37Pyo, S.G., Chang, Y.W. and Kim, N.J.: Microstructure and mechanical properties of duplex TiAl alloys containing Mn. Metals Mater. 1, 107 (1995).CrossRefGoogle Scholar
38Appel, F., Lorenz, U., Sparka, U. and Wagner, R.: Effects of dislocation dynamics and microstructure on crack growth mechanisms in two-phase titanium aluminide alloys. Intermetallics 6, 603 (1998).CrossRefGoogle Scholar
39Appel, F., Christoph, U. and Wagner, R.: An electron microscope study of deformation and crack propagation in (α2+ γ) titanium aluminides. Philos. Mag. A 72, 341 (1995).CrossRefGoogle Scholar
40Schechtman, D., Blackburn, M.J. and Lipsitt, H.A.: Plastic deformation of TiAl. Metall. Trans. A 5, 1373 (1974).CrossRefGoogle Scholar
41Inui, H., Toda, Y. and Yamaguchi, M.: Plastic deformation of single crystals of a DO19 compound with an off-stoichiometric composition (Ti-36.5 at.% Al) at room temperature. Philos. Mag. A 67, 1315 (1993).CrossRefGoogle Scholar