Microstructural evolution and FCC twinning behavior during hot deformation of high temperature titanium alloy Ti65

doi:10.1016/j.jmst.2020.02.026

Abstract

Abstract:

Although the development of titanium alloys with working temperatures above 600 ℃ faces enormous difficulties and challenges, the related research has not stopped. In the present work, detailed analyses on microstructure evolution and hot deformation behavior of a new temperature resistant 650 ℃ titanium alloy Ti65 were investigated from micrometer scale to nanometer scale. The results revealed that lamellar α grains gradually fragmentized and spheroidized during the α + β phase region compression and the orientation of the c-axis of α grains gradually aligned to radial directions, forming two high Schmid factors (SFs) value texture eventually with the increase of strain to 0.7. Moreover, there were some strengthening characters in the α + β phase region such as lenticular α_s and nano silicide (TiZr)₆Si₃. In the β phase region, fine equiaxed dynamic recrystallized (DRX) β grains were formed. Besides, the variant selection of α′ martensite followed Burgers orientation relationship during the compression process. The main deformation mechanisms of the α + β phase region were dislocation slip and orientation dependent spheroidization. Whereas, the deformation process in the β phase region was controlled by β grain DRX. Interestingly, many nano scale FCC twins were generated at the interface of α′ lath during deforming in the β phase region, which was firstly observed in Ti65 alloy.

Key words: High temperature titanium alloy, Hot deformation, Microstructure evolution, Texture, FCC twin

Zhixin Zhang, Jiangkun Fan, Bin Tang, Hongchao Kou, Jian Wang, Xin Wang, Shiying Wang, Qingjiang Wang, Zhiyong Chen, Jinshan Li. Microstructural evolution and FCC twinning behavior during hot deformation of high temperature titanium alloy Ti65[J]. J. Mater. Sci. Technol., 2020, 49: 56-69.

Figures/Tables 20

Fig. 1. (a) Initial microstructure, (b) EBSD map (IPF) and (c) three dimensional ODF map of Ti65 alloy.

Fig. 2. (a) The heating and deformation schedule for thermal compression process and (b) schematic representation of compression direction.

Fig. 3. (a) Flow stress-strain curve with the corresponding microstructure of Ti65 alloy deformed at 960 ℃ and 0.1 s-1 with different true strain: (b) 0.04; (c) 0.4; (d) 0.7.

Fig. 4. EBSD inverse pole figures (IPF) and the corresponding pole figures (PF) of Ti65 alloy deformed at 960 ℃ and 0.1 s-1 with different strain: (a) (b) 0.04; (c) (d) 0.4; (e) (f) 0.7.

Fig. 5. Three dimensional ODF (Euler space) and constant φ2 = 0°/30° ODF maps of Ti65 alloy deformed at 960 ℃ and 0.1 s-1 with different true strain: (a) (b) (c) 0.04; (d) (e) (f) 0.4; (g) (h) (i) 0.7.

Fig. 6. Schmid factors (SF) histogram of α phase with Basal < a>, Prismatic < a> and Pyramidal < a> slip systems for Ti65 alloy deformed at 960 ℃ and 0.1 s-1 with different true strain: (a) 0.04; (b) 0.4; (c) 0.7.

Table 1 SFs of Basal, Prismatic and Pyramidal slip systems for different texture components formed at 0.4 and 0.6 strain.

Slip system	Texture component
Slip system	($\bar{1}$2$\bar{1}$5)[1$\bar{2}$11]	($\bar{1}$2$\bar{1}$2)[4$\bar{5}$16]	(02$\bar{2}$3)[0$\bar{1}$11]
Basal < a> (0001)[11$\bar{2}$0]	0	0.13	0.04
Prismatic < a> (1$\bar{1}$00)[11$\bar{2}$0]	0.5	0.47	0.35
Pyramidal < a> (1$\bar{1}$01)[11$\bar{2}$0]	0.40	0.31	0.26

Fig. 7. KAM maps of Ti65 alloy deformed at 960℃and 0.1 s-1 with different true strain (a) 0.04, (b) 0.4, (c) 0.7 and (d) KAM histogram.

Fig. 8. Grain boundary contrast maps for Ti65 alloy deformed at 960 ℃ and 0.1 s-1 with different true strain (a) 0.04, (b) 0.4, (c) 0.7 and (d) statistical diagram of misorientation angle, (e) the α grain size histogram. The high-angle boundaries (HABs) with misorientation over 15 deg and the low-angle boundaries (LABs) with misorientation at 2 to 15 deg are depicted as black lines and red lines, respectively.

Fig. 9. (a) Flow stress-strain curve with the corresponding microstructure of Ti65 alloy deformed at 1080 ℃ and 0.1 s-1 with different true strain: (b) 0.04; (c) 0.4; (d) 0.7.

Fig. 10. IPF and the corresponding PF of Ti65 alloy deformed at 1080℃ and 0.1s-1 with different true strain: (a) (b) 0.04; (c) (d) 0.4; (e) (f) 0.7.

Fig. 11. Three dimensional ODF (Euler space) and constant φ2 = 0°/30° ODF maps of Ti65 alloy deformed at 1080 ℃ and 0.1 s-1 with different true strain: (a) (b) (c) 0.04; (d) (e) (f) 0.4; (g) (h) (i) 0.7.

Fig. 12. Schmid factors histogram of α phase with Basal < a>, Prismatic < a> and Pyramidal < a> slip systems for Ti65 alloy deformed at 1080 ℃ and 0.1 s-1 with different true strain: (a) 0.04; (b) 0.4; (c) 0.7.

Fig. 13. KAM maps for Ti65 alloy deformed at 1080 ℃ with different true strain (a) 0.04, (b) 0.4, (c) 0.7 and (d) KAM histogram.

Fig. 14. Grain boundary contrast maps with true strain (a) 0.04, (b) 0.4, (c) 0.7 and recrystallized maps with true strain (e) 0.4, (f) 0.7 for Ti65 alloy deformed at 1080 ℃and 0.1 s-1 and (d) statistical diagram of misorientation angle.

Fig. 15. (a) (b) TEM images of Ti65 alloy deformed at 960 ℃ (0.1 s-1) with 0.7 strain and (c) corresponding EDS results of silicide in (b). (d) (e) TEM images deformed at 1080 ℃ (0.1 s-1) with 0.7 strain and (f) the SAED pattern of FCC twins highlighted in (e). The SAED patterns corresponding to the TEM images are embedded in the picture respectively.

Fig. 16. The schematic diagram of the precipitation process during the hot deformation of Ti65 alloy.

Fig. 17. (a) and (b) Plots of ln(strain rate ε˙) vs. lnsinhασ for various deformation temperatures and (c) (d) 1/T vs. lnsinhασ for various strain rates.

Fig. 18. FCC twins in Ti65 alloy deformed in the β phase field: (a) DF TEM image and its corresponding magnified BF TEM image is inset; (b) HRTEM image of FCC twins; (c) Fast Fourier-filtered (FFT) pattern and (d) Inverse fast Fourier-filtered (IFFT) image transformed from red frame in (b).

Table 2 FCC phase in different titanium alloys.

Alloy	Generating condition	Lattice parameter a(nm)
CP-Ti [46]	Cryogenic channel-die compression	0.4302
Ti-6Al-4 V [47]	High energy shot peening	0.4158
Ti-20Zr-6.5Al-4 V [48]	Solution treatment at 950℃	0.4385
Ti65	Compression in the β phase region	0.4321

References 48

[1]	Christoph Leyens, Manfred Peters, Darmstadt, 2004, pp. 23-25.
[2]	J. Matthew, Titanium: A Technical Guide, 2000, pp. 18.
[3]	R.W. Evans, R.J. Hull, B. Wilshire, J. Mater. Process. Technol. 56 (1-4) (1996) 492-501.
[4]	Shouyong Wei, Wei-min Shi, Ding-chun Wang, Chin. J. Nonferrous Met. 20(S1) (2010) 801-806.
[5]	I. Weiss, S. Semiatin, Mater. Sci. Eng. A 263 (2) (1999) 243-256.
[6]	Q.J. Wang, J.R. Liu, R. Yang, J. Aeronaut. Mater. 34 (4) (2014) 1-26.
[7]	J.Q. Qi, Y. Chang, Y.Z. He, Mater. Des. 99 (2016) 421-426.
[8]	Wei Shouyong, Shi Weimin, Guo Jialin, J. Chin. J. Nonferrous Met. 23 (1) (2013) 121-124.
[9]	H. Kestler, H. Muahrabi, H. Remner, Titanium Sci. Technol. (1995) 1171-1178.
[10]	Michael Y. Mendoza, Peyman Samimi, David A. Brice, et al., Metall. Mater. Trans. A (48A) (2017) 3594-3605.
[11]	W.J. Zhanga, X.V. Songa, sx. Hui, et al., Mater. Sci. Eng. A 595 (2014) 159-164. DOI URL
[12]	R.W. Evans, R.J. Hull, B. Wilshire, J. Mater. Process. Technol. 56 (1996) 492-501. DOI URL
[13]	Wenwen Peng, Weidong Zeng, Qingjiang Wang, et al., Mater. Sci. Eng. A571 (2013) 116-122.
[14]	Feng Sun, Jinshan Li, Hongchao Kou, Mater. Sci. Eng. A 626 (2015) 247-253. DOI URL
[15]	Min Zhou, Mater. Sci. Eng. A 245 (1998) 29-38. DOI URL
[16]	Wenwen Peng, Weidong Zeng, Qingjiang Wang, Mater. Des. 51 (2013) 95-104.
[17]	Wenwen Peng, Weidong Zeng, Qingjiang Wang, Mater. Sci. Eng. A 593 (2014) 16-23.
[18]	Guohua Zhao, Xin Xu, David Dye, et al., Acta Mater. 183 (2020) 155-164. DOI URL
[19]	Yan Chong, Guanyu Deng, Jangho Yi, et al., J. Alloys. Compd. 811 (2019), 152040.
[20]	P. Ahmadian, S.M. Abbasi, M. Morakabati, Mater. Today Commun. 13 (2017) 332-345.
[21]	K.V. Sai Srinadh, Nidhi Singh, V Singh, Bull. Mater. Sci. 30 (2007) 595-600. DOI URL
[22]	Jingyuan Shen, Yu Sun, Yongquan Ning, et al., Mater. Charact. 153 (2019) 304-317. DOI URL
[23]	Wang Ke, Miaoquan Li, Qing Liua, Mater. Charact. 120 (2016) 115-123. DOI URL
[24]	Z.B. Zhao, Q.J. Wang, J.R. Liu, et al., Metallurg. Mater. Trans. A (2018) 1-10.
[25]	Wenyuan Li, Zhiyong Chen, Jianrong Liu, et al., Mater. Sci. Eng. A 688 (2017) 322-329.
[26]	Sun Feng, Li Jinshan, Kou Hongchao, et al., Rare Met. Mater. Eng. 44 (4) (2015) 0848-0853.
[27]	O. Engler, V. Randle, Introduction to Texture Analysis: Macrotexture, Microtexture, and Orientation Mapping, CRC Press Taylor, New York, 2009, pp. 21-27.
[28]	Y.N. Wang, J.C. Huang, Mater. Chem. Phys. 81 (2003) 11-26. DOI URL
[29]	Richard W. Hertzberg, Richard P. Vinci, Jason L. Hertzberg, Deformation and Fracture Mechanics of Engineering Materials, WILEY-VCH Verlag GmbH & Co, KGaA, 1995, pp. 7-8.
[30]	M.G. Jiang, C. Xu, H. Yan, et al., Acta Mater. 157 (2018) 53-71.
[31]	Eralp Demir, Dierk Raabe, Nader Zaafarani, et al., Acta Mater. 57 (2009) 559-569.
[32]	S. Birosca, F. Di Gioacchino, S. Stekovic, et al., Acta Mater. 74 (2014) 110-124.
[33]	Ehsan Farabi a, Peter D.Hodgson a, Gregory S. Rohrer, Acta Mater. 154 (2018) 147-160. DOI URL
[34]	Jiangkun Fan, Jinshan Li, Yudong Zhang, et al. Adv. Eng. Mater. 19 (2017). DOI URL PMID
[35]	Hongwei Li, Xinxin Sun, He Yang, Int. J. Plast. 87 (2016) 154-180. DOI URL
[36]	Shibayan Roy, Satyam Suwas, Scr. Mater. 154 (2018) 1-7. DOI URL
[37]	E. Ghasemi, A. Zarei-Hanzaki, E. Farabi, et al., J. Alloys. Compd. 695 (2017) 1706-1718. DOI URL
[38]	C.K. Yan, A.H. Feng, S.J. Qu, et al., Acta Mater. 154 (2018) 311-324. DOI URL
[39]	Shibayan Roy, Satyam Suwas, Acta Mater. 134 (2017) 283-301.
[40]	Hossein Beladi, Qi Chao S. Gregory, Acta Mater. 80 (2014), 478-48.
[41]	Binguo Fu, Hongwei Wang, Chunming Zou, et al., Mater. Charact. 99 (2015) 17-24.
[42]	H.J. McQueen, N.D. Ryan, Mater. Sci. Eng. A 322 (2002) 43-63. DOI URL
[43]	K. Wang, M.Q. Li, Mater. Sci. Eng. A 600 (2014) 122-128.
[44]	P. Wanjara, M. Jahazi, H. Monajati, S. Yue, J.-P. Immarigeon, Mater. Sci. Eng. A 396 (2005) 50-60.
[45]	F. Warchomickaa, C. Poletti, Mater. Sci. Eng. A 528 (2011) 8277-8285.
[46]	D.H. Hong, T.W. Lee, S.H. Lim, et al., Scr. Mater. 69 (2013) 405-408.
[47]	Y.G. Liu, M.Q. Li, H.J. Liu, Scr. Mater. 119 (2016) 5-8.
[48]	R. Jing, C.Y. Liu, M.Z. Ma, J. Alloys. Compd. 552 (2013) 202-207.