Increasing high-temperature fatigue resistance of polysynthetic twinned TiAl single crystal by plastic strain delocalization

doi:10.1016/j.jmst.2021.03.050

Abstract

Abstract:

Polysynthetic twinned (PST) TiAl single crystal possesses great potentials for high-temperature applications due to its excellent combination of strength, ductility and creep resistance. However, a critical property for high-temperature application of such material involving high-temperature fatigue properties remains unknown. Here, the high-temperature high-cycle fatigue performance of PST TiAl single crystal has been studied. The result shows that PST TiAl single crystal can withstand more than 10⁷ cyclic loadings at 975 ℃ under a stress amplitude of 270 MPa, which is significantly higher than traditional TiAl alloys. Experimental observations and atomistic simulations indicate that the improvement of fatigue resistance is attributed to the plastic strain delocalization in uniform lamellar structure, and the plastic deformation is well-distributed and sufficient in each lamella. Even in the α₂ lamella with difficult slippage, a large number of stacking fault structures can be observed. The 〈c + a〉 dislocations in α₂ tend to dissociate into a Frank partial with b = 1/6 <2$\bar{2}$0$\bar{3}$>, forming a ribbon of I1 fault which ensures the continuity of deformation.

Key words: TiAl, Single crystal, Fatigue, High temperature, Strain delocalization

Yang Chen, Yuede Cao, Zhixiang Qi, Guang Chen. Increasing high-temperature fatigue resistance of polysynthetic twinned TiAl single crystal by plastic strain delocalization[J]. J. Mater. Sci. Technol., 2021, 93: 53-59.

Figures/Tables 8

Fig. 1. Macrograph of high-temperature fatigue specimen prepared with PST TiAl single crystal and the corresponding lamellar microstructure. (a) Macrograph of high-temperature fatigue specimen; (b) Bright-field TEM image showing the original γ/α2 lamellar structure before the tensile test; (c) High-resolution TEM image showing the γ/α2 interface structure.

Fig. 2. (a) Optimized simulation model; (b) Stress-strain curve of the model with tensile along the y axis.

Fig. 3. Deformation structure of PST TiAl single crystals after high-cycle fatigue deformation at 975 ℃. (a) Bright-field TEM image showing the typical morphology of lamellar structure in PST TiAl single crystals with 0° lamellar orientation after high-cycle fatigue deformation at 975 ℃; (b) Deformation substructure in SF-type domains; (c) Deformation substructure in V-type domains (stacking fault structures were marked by white arrows); (d) High magnification image of the red dashed box in Fig. 3(c).

Fig. 4. Atomic-scale microstructure of a typical stacking fault in the PST TiAl single crystals after high-cycle fatigue deformation at 975 ℃. (a) HRTEM image; (b) Corresponding SAED pattern taken along the > 2$\bar{1}$10< zone axis; (c) Enlarged images in white dotted frame of this fault in Fig. 4a (stacking fault structures were marked by white arrows); (d), (e) and (f), Enlarged images in red, blue and gold dotted frame of this fault in Fig. 4c respectively.

Fig. 5. Atomistic structure of the relaxed γ/α2 interface showing misfit dislocation and interface structure pattern. (a) The relaxed interface structure is colored by potential energy; (b) The interface stacking regions are colored by CNA.

Fig. 6. Amplitude stress and dislocation density variable with cumulative cycles at stress ratio R = 0.1 with MD simulations. (a) Maximum amplitude stress of 4.5 GPa varies with cumulative cycles; (b) Maximum amplitude stress of 4.0 GPa varies with cumulative cycles; (c) Dislocation density of the maximum amplitude stress of 4.5 GPa.

Fig. 7. Deformations for different cumulative cycles N. (a) N = 0; (b) N = 4.5; (c) N = 5.5; (d) N = 6.5. The structures are identified by the CNA, HCP structure is colored by yellow and FCC is colored by blue.

Fig. 8. Evolutions of shear strain for different cumulative cycles N. (a) N = 0; (b) N = 4.5; (c) N = 5.5; (d) N = 6.5.

References 54

[1]	Subra Suresh, Fatigue of Materials, (2nd ed)(1998) London.
[2]	S.K. Jha, J.M. Larsen, A.H. Rosenberger, Acta Mater, 53(2005), pp. 1293-1304.
[3]	T.E.J. Edwards, Mater. Sci. Technol., 34(2018), pp. 1919-1939.
[4]	F. Ellyin, Fatigue Damage, Crack Growth and Life Prediction, (1st ed)(1997) London.
[5]	J. Schijve, Fatigue of Structures and Materials, (2nd ed), Springer Netherlands (2009).
[6]	H.Y. Yasuda, T. Nakano, Y. Umakoshi, Philos. Mag., 71(1995), pp. 127-138.
[7]	Y. Murakami, Effects of Small Defects and Nonmetallic Inclusion, Metal Fatigue(1993)
[8]	H.N. Wu, D.S. Xu, H. Wang, R. Yang, J. Mater. Sci. Technol., 32(2016), pp. 1033-1042.
[9]	J.J. Kruzic, J.P. Campbell, R.O. Ritchie, Acta Mater, 47(1999), pp. 801-816.
[10]	Y. Mine, K. Takashima, P. Bowen, Mater. Sci. Eng. A, 532(2012), pp. 13-20.
[11]	Y. Umakoshi, H.Y. Yasuda, T. Nakano, Intermetallics, 4(1996), pp. S65-S75.
[12]	H.Y. Yasuda, T. Nakano, Y. Umakoshi, Philos. Mag., 73(1996), pp. 1035-1051.
[13]	Y. Umakoshi, T. Nakano, Acta Metall. Mater., 41(1993), pp. 1155-1161.
[14]	F. Appel, H. Clemens, F.D. Fischer, Prog. Mater. Sci., 81(2016), pp. 55-124.
[15]	M.H. Yoo, Metall. Trans. A, 12(1981), pp. 409-418.
[16]	Y. Umakoshi. T. Nakano, T. Takenaka, K. Sumimoto, T. Yamane, Acta Mater, 41(1993), pp. 1149-1154.
[17]	K. Kishida, J. Yoshikawa, H. Inui, M. Yamaguchi, Acta Mater, 47(1999), pp. 3405-3410.
[18]	M. Legros, Y. Minonishi, D. Caillard, Philos. Mag., 76(1997), pp. 1013-1032.
[19]	M. Legros, Y. Minonishi, D. Caillard, Philos. Mag., 76(1997), pp. 995-1011.
[20]	Y. Umakoshi, T. Nakano, ISIJ Int, 32(1992), pp. 1339-1347.
[21]	S. Yokoshima, M. Yamaguchi, Acta Mater, 44(1996), pp. 873-883.
[22]	L. Heatherly, E.P. George, C.T. Liu, M. Yamaguchi, Intermetallics, 5(1997), pp. 281-288.
[23]	A. Jesus Palomares-Garcia, M. Teresa Perez-Prado, J. Mikel Molina-Aldareguia, Mater. Des., 146(2018), pp. 81-95.
[24]	Y.H. Lu, Y.G. Zhang, L.J. Qiao, Y.B. Wang, C.Q. Chen, W.Y. Chu, Mater. Sci. Eng. A, 289(2000), pp. 91-98.
[25]	S.A. Court, J.P.A. Löfvander, M.H. Loretto, H.L. Fraser, Philos. Mag., 61(1990), pp. 109-139.
[26]	G. Chen, Y.B. Peng, G. Zheng, Z.X. Qi, M.Z. Wang, H.C. Yu, C.L. Dong, C.T. Liu, Nat. Mater., 15(2016), pp. 876-881.
[27]	T.D. Wood, D.K. Dewald, D.E. Mikkola, Surf. Eng., 15(1999), pp. 335-339.
[28]	Y. Zhou, J.Q. Wang, B. Zhang, W. Ke, E.H. Han, Intermetallics, 24(2012), pp. 7-14.
[29]	D.P. Wang, Z.X. Qi, H.T. Zhang, G. Chen, Y. Lu, B.A. Sun, C.T. Liu, Mater. Sci. Eng. A, 732(2018), pp. 14-20.
[30]	N. He, Z.X. Qi, Y.X. Cheng, J.P. Zhang, L.L. He, G. Chen, Intermetallics, 128(2021), Article 106995.
[31]	G. Chen, F.R. Chen, Z.X. Qi, C.M. Feng, Y.D. Cao, H. Xu, G. Zheng, Journal of Vibration, Measurment & diagnosis, 39(2019), pp. 915-1126.
[32]	G. Chen, G. Zheng, Z.X. Qi, J.P. Zhang, P. Li, J.L. Cheng, Z.W. Zhang, Acta Metall. Sin., 54(2018), pp. 669-681. (in Chinese)
[33]	S. Plimpton, J. Comput. Phys., 117(1995), pp. 1-19.
[34]	M.S. Daw, M.I. Baskes, Phys. Rev. B, 29(1984), pp. 6443-6453.
[35]	D.S. Xu, H. Wang, R. Yang, P. Veyssière, Acta Mater, 56(2008), pp. 1065-1074.
[36]	Z. Cheng, H.F. Zhou, Q.H. Lu, H.J. Gao, L. Lu, Science, 362 (2018), p.559.
[37]	W.G. Hoover, Phys. Rev. A, 31(1985), pp. 1695-1697.
[38]	W.G. Hoover, Phys. Rev. A, 34(1986), pp. 2499-2500.
[39]	A. Stukowski, Model Simul. Mater. Sci. Eng., 18(2010), Article 015012.
[40]	D. Faken, H. Jónsson, Comput. Mater. Sci., 2(1994), pp. 279-286.
[41]	Y. Umakoshi, H.Y. Yasuda, T. Nakano, Mater. Sci. Eng. A, 192-193(1995), pp. 511-517.
[42]	D.L. Zhang, L. Jiang, J.M. Schoenung, S. Mahajan, E.J. Lavernia, Philos. Mag., 95(2015), pp. 3823-3844.
[43]	K. Wei, R. Hu, D.D. Yin, L.R. Xiao, S. Pang, Y. Cao, H. Zhou, Y.H. Zhao, Y.T. Zhu, Acta Mater, 206(2021), Article 116604.
[44]	S.R. Agnew, L. Capolungo, C.A. Calhoun, Acta Mater, 82(2015), pp. 255-265.
[45]	E.M. Bringa, A. Caro, Y.M. Wang, M. Victoria, J.M. McNaney, B.A. Remington, R.F. Smith, B.R. Torralva, H.V. Swygenhoven, Science, 309(2005), pp. 1838-1841.
[46]	Y.M. Wang, M.W. Chen, F.H. Zhou, E. Ma, Nature, 419(2002), pp. 912-915.
[47]	M.A. Meyers, A. Mishra, D.J. Benson, Prog. Mater. Sci., 51(2006), pp. 427-556.
[48]	Q.S. Pan, H.F. Zhou, Q.H. Lu, H.J. Gao, L. Lu, Nature, 551(2017), pp. 214-217.
[49]	Y.J. Du, J. Shen, Y.L. Xiong, Q.D. Li, H.Z. Fu, Metall. Mater. Trans. A, 50(2019), pp. 4166-4177.
[50]	R.R. Chen, Q. Wang, Z.C. Zhou, Y.Q. Su, J.J. Guo, H.S. Ding, H.Z. Fu, J. Alloys Compd., 801(2019), pp. 166-174.
[51]	H. Wu, G.H. Fan, Prog. Mater. Sci., 113(2020), Article 100675.
[52]	T.E.J. Edwards, F.D. Gioacchino, R.M. Moreno, W.J. Clegg, Scr. Mater., 118(2016), pp. 46-50.
[53]	T.E.J. Edwards, F.D. Gioacchino, A.J. Goodfellow, G. Mohanty, J. Wehrs, J. Michler, W.J. Clegg, Acta Mater, 163(2019), pp. 122-139.
[54]	T.E.J. Edwards, Mater. Sci. Technol., 34(2018), pp. 1-21.