Effects of Boron Addition on the Microstructure and Mechanical Properties of γ′-Strengthened Directionally Solidified CoNi-Base Superalloy

doi:10.1007/s40195-024-01715-y

Abstract

Abstract:

The effects of B addition on microstructure and mechanical properties of a γ′-strengthened CoNi-base superalloy are investigated. The addition of B leads to a substantial increase in the volume fraction of both the eutectic structure and borides. The CoNi-base alloy shows a high solubility limit for the element B. Borides become noticeable in the area surrounding the eutectic structure after the B level exceeds 0.46 at.%. It is found that the compression property and stress rupture life of the 4W2Ta alloys exhibit an initial rise followed by a subsequent drop as the B content gradually increases from 0.08 to 0.78 at.%. The 4W2Ta0.46B alloy demonstrates the most excellent high-temperature strength and stress rupture life, revealing that a moderate amount of B in the alloy noticeably enhances its mechanical properties by enhancing the grain boundary cohesion.

Key words: CoNi-base superalloy, Borides, Grain boundary, Microstructure, Mechanical properties

Shasha Qu, Yingju Li, Bingyu Lu, Cuiping Wang, Yuansheng Yang. Effects of Boron Addition on the Microstructure and Mechanical Properties of γ′-Strengthened Directionally Solidified CoNi-Base Superalloy[J]. Acta Metallurgica Sinica (English Letters), 2024, 37(8): 1438-1452.

Figures/Tables 17

Fig. 1 Crack at grain boundary in the 4W2Ta alloy after compression at 900 °C

Table 1 Nominal composition of the experimental alloys

Alloys	Chemical composition (at.%)
Alloys	Co	Ni	Al	W	Ti	Ta	B
4W2Ta0.08B	Bal.	30.07	9.75	4.10	3.97	1.96	0.08
4W2Ta0.16B	Bal.	30.07	9.75	4.08	4.00	1.98	0.16
4W2Ta0.46B	Bal.	30.05	9.77	4.08	3.96	1.97	0.46
4W2Ta0.78B	Bal.	29.90	9.70	4.04	3.96	1.94	0.78

Fig. 2 Cross section micrographs of directionally solidified 4W2Ta alloys with different B contents: a1, b1 B-free 4W2Ta, a2, b2 4W2Ta0.08B, a3, b3 4W2Ta0.16B, a4, b4 4W2Ta0.46B, a5, b5 4W2Ta0.78B alloy

Fig. 3 EDS spectrum of the phase indicated by the red arrow in Fig. 2b4

Fig. 4 Element distribution of the directionally solidified microstructure of 4W2Ta0.46B alloy with SIMS

Fig. 5 Volume fraction of eutectic structure of 4W2Ta alloys with different B contents

Fig. 6 Backscattered electron (BSE) images of directionally solidified microstructure of the 4W2Ta alloys with different B contents: a 4W2Ta0.08B, b 4W2Ta0.16B, c 4W2Ta0.46B, d 4W2Ta0.78B alloy

Fig. 7 SEM micrographs showing microstructures of alloys after solution treatment at 1250 °C for 24 h: a B-free 4W2Ta, b 4W2Ta0.08B, c 4W2Ta0.16B, d 4W2Ta0.46B, e 4W2Ta0.78B alloy

Fig. 8 SEM micrographs showing microstructures of alloys after aging treatment at 900 °C for 24 h: a 4W2Ta0.08B, b 4W2Ta0.16B, c 4W2Ta0.46B, d 4W2Ta0.78B alloy

Fig. 9 SEM-EDS characterization of element distribution of 4W2Ta0.78B after aging at 900 °C for 24 h

Fig. 10 DTA curves of 4W2Ta alloys with B-containing

Fig. 11 Temperature dependence of 0.2% flow stress of 4W2Ta alloys with different B contents

Fig. 12 TEM Bright-field images of the microstructure of 4W2Ta0.16B alloy after compression deformation to 10% at a room temperature, b 600 °C, c 800 °C, d 900 °C

Fig. 13 TEM Bright-field images of the microstructure of 4W2Ta0.46B alloy after compression deformation to 10% at a room temperature, b 600 °C, c 800 °C, d 900 °C

Fig. 14 TEM Bright-field images of the microstructure of 4W2Ta0.78B alloy after compression deformation to 10% at a room temperature, b 600 °C, c 800 °C, d 1000 °C

Fig. 15 Stress-rupture life of 4W2Ta alloys with different B contents at 900 °C/140 MPa

Fig. 16 SEM images of the fracture surface after stress-rupture tests at 900 °C/140 MPa: a 4W2Ta, b 4W2Ta0.16B, c 4W2Ta0.46B, d 4W2Ta0.78B alloy

References 46

[1]	J. Sato, T. Omori, K. Oikawa, I. Ohnuma, R. Kainuma, K. Ishida, Science 312, 90 (2006)
[2]	R.C. Reed, The Superalloys: Fundamentals and Applications (Cambridge University Press, New York, 2006)
[3]	T.M. Pollock, J. Dibbern, M. Tsunekane, J. Zhu, A. Suzuki, JOM 62, 58 (2010)
[4]	S. Kobayashi, Y. Tsukamoto, T. Takasugi, H. Chinen, T. Omori, K. Ishida, S. Zaefferer, Intermetallics 17, 1085 (2009)
[5]	Y. Tsukamoto, S. Kobayashi, T. Takasugi, Mater. Sci. Forum 654-656, 448 (2010)
[6]	A. Suzuki, G.C. DeNolf, T.M. Pollock, Scr. Mater. 56, 385 (2007)
[7]	C. Jiang, Scr. Mater. 59, 1075 (2008)
[8]	H.Y. Yan, V.A. Vorontsov, D. Dye, Intermetallics 48, 44 (2014)
[9]	A. Bauer, S. Neumeier, F. Pyczak, R.F. Singer, M. Göken, Mater. Sci. Eng. A 550, 333 (2012)
[10]	G. Feng, H. Li, S.S. Li, J.B. Sha, Scr. Mater. 67, 499 (2012)
[11]	A. Mottura, A. Janotti, T.M. Pollock, Intermetallics 28, 138 (2012)
[12]	L. Shi, J.J. Yu, C.Y. Cui, X.F. Sun, Mater. Sci. Eng. A 646, 45 (2015)
[13]	L. Shi, J.J. Yu, C.Y. Cui, X.F. Sun, Mater. Lett. 149, 58 (2015)
[14]	K. Shinagawa, T. Omori, J. Sato, K. Oikawa, I. Ohnuma, R. Kainuma, K. Ishida, Mater. Trans. 49, 1474 (2008)
[15]	M.S. Titus, Y.M. Eggeler, A. Suzuki, T.M. Pollock, Acta Mater. 82, 530 (2015)
[16]	E.A. Lass, Metal. Mater. Trans. A 48, 2443 (2017)
[17]	Y.M. Eggeler, J. Müller, M.S. Titus, A. Suzuki, T.M. Pollock, E. Spiecker, Acta Mater. 113, 335 (2016)
[18]	C.H. Chu, Q.Y. Guo, Y. Guan, Z.X. Qiao, Y.C. Liu, Mater. Sci. Eng. A 833, 142587 (2022)
[19]	A. Bezold, N. Volz, M. Lenz, N. Karpstein, C.H. Zenk, E. Spiecker, M. Göken, S. Neumeier, Acta Mater. 227, 117702 (2022)
[20]	S.S. Qu, Y.J. Li, M. Tong, C.P. Wang, Y.S. Yang, Mater. Sci. Eng. A 823, 141776 (2021)
[21]	C.S. Lee, G.W. Han, R.E. Smallman, D. Feng, J.K.L. Lai, Acta Mater. 47, 1823 (1999)
[22]	T.H. Chuang, Mater. Sci. Eng. A 141, 169 (1991)
[23]	Y.L. Chiu, A.H.W. Ngan, Scr. Mater. 40, 27 (1999)
[24]	B.I. Kang, C.H. Han, Y.K. Shin, J.I.L. Youn, Y.J. Kim, J. Mater. Eng. Perform. 28, 7025 (2019)
[25]	Q. Hu, L. Liu, X.B. Zhao, S.F. Gao, J. Zhang, H.Z. Fu, Trans. Nonferrous Met. Soc. China 23, 3257 (2013)
[26]	D. Wu, T.T. Yao, D.Z. Li, S.P. Lu, Mater. Sci. Eng. A 731, 21 (2018)
[27]	D. Lemarchand, E. Cadel, S. Chambreland, D. Blavette, Philos. Mag. A 82, 1651 (2009)
[28]	M.J. Zhao, Z.F. Guo, H. Liang, L.J. Rong, Mater. Sci. Eng. A 527, 5844 (2010)
[29]	B.P. Wu, L.H. Li, J.T. Wu, Z. Wang, Y.B. Wang, X.F. Chen, J.X. Dong, J.T. Li, Int. J. Miner. Metall. Mater. 21, 1120 (2014)
[30]	A. Sharma, S. Dixit, N. Baler, P. Agrawal, S.K. Makineni, K. Chattopadhyay, Mater. Sci. Eng. A 855, 143899 (2022)
[31]	C.T. Liu, C.L. White, J.A. Horton, Acta Mater. 33, 213 (1985)
[32]	D. Mukherji, J. Rösler, M. Krüger, M. Heilmaier, M.C. Bölitz, R. Völkl, U. Glatzel, L. Szentmiklósi, Scr. Mater. 66, 60 (2012)
[33]	K. Shinagawa, T. Omori, K. Oikawa, R. Kainuma, K. Ishida, Scr. Mater. 61, 612 (2009)
[34]	P.J. Bocchini, C.K. Sudbrack, R.D. Noebe, D.C. Dunand, D.N. Seidman, Mater. Sci. Eng. A 682, 260 (2017)
[35]	M. Kolb, L.P. Freund, F. Fischer, I. Povstugar, S.K. Makineni, B. Gault, D. Raabe, J. Müller, E. Spiecker, S. Neumeier, M. Göken, Acta Mater. 145, 247 (2018)
[36]	B.C. Yan, J. Zhang, L.H. Lou, Mater. Sci. Eng. A 474, 39 (2008)
[37]	Z.H. Yu, B.L. Liu, X.W. Zhai, J.F. Qiang, Z.H. Mei, Z.B. Fei, Mater. Res. Expr. 6, 116544 (2019)
[38]	H. Xu, Y.H. Zhang, H.D. Fu, F. Xue, X.Z. Zhou, J.X. Xie, J. Alloy. Compd. 891, 161965 (2022)
[39]	Z.D. Fan, C.C. Wang, C. Zhang, Y.H. Yu, H. Chen, Z.G. Yang, Mater. Sci. Eng. A 735, 114 (2018)
[40]	J.L. Li, J.Q. Zhang, Z. Li, Q. Wang, C. Dong, F. Xu, L.X. Sun, P.K. Liaw, J. Mater. Sci. Technol. 186, 174 (2024)
[41]	A. Suzuki, T.M. Pollock, Acta Mater. 56, 1288 (2008)
[42]	V. Paidar, D.P. Pope, V. Vitek, Acta Metall. 32, 435 (1984)
[43]	X.G. Wang, J.L. Liu, T. Jin, X.F. Sun, Mater. Des. 63, 286 (2014)
[44]	K.J. Hemker, M.J. Mills, Philos. Mag. A 68, 305 (1993)
[45]	P. Kontis, H.A.M. Yusof, S. Pedrazzini, M. Danaie, K.L. Moore, P.A.J. Bagot, M.P. Moody, C.R.M. Grovenor, R.C. Reed, Acta Mater. 103, 688 (2016)
[46]	P.J. Zhou, J.J. Yu, X.F. Sun, H.R. Guan, Z.Q. Hu, Mater. Sci. Eng. A 491, 159 (2008)