Microstructure evolution and mechanical property characterization of a nickel-based superalloy at the mesoscopic scale

doi:10.1016/j.jmst.2020.02.021

Abstract

Abstract:

Nickel-based superalloys have become the critical materials of micro-parts depending on outstanding mechanical properties. The effects of the grain size and precipitates on the mechanical properties at the mesoscopic scale are difficult to be revealed using conventional macroscopic material constitutive models. In the present study, the microstructure evolution of the γ″ phase and the tensile mechanical properties of a nickel-based superalloy at the mesoscopic scale were investigated systematically. Three variants of γ″ phases precipitated corresponding to [00], [00] and [001] orientations of the matrix γ phase. The quantitative statistics results showed that as the aging time increases, the particle size and volume fraction of the γ″ phase increase. As the grain size increases, the flow stress decreases due to the dwindling of grain boundary strengthening. Furthermore, the precipitation strengthening of γ″ and γ′ phases induces the increase of flow stress. An important conclusion is drawn that the size effect at the mesoscopic scale depends not only on the sample size and grain size but also on the particle size and volume fraction of the precipitates. The established constitutive model which considers grain boundary strengthening, precipitation strengthening and solid solution strengthening can accurately describe the flow stress characteristics of nickel-based superalloys at the mesoscopic scale.

Key words: Superalloy, Microstructure evolution, Size effect, Tensile deformation, Mesoscale constitutive model

Qiang Zhu, Gang Chen, Chuanjie Wang, Lukuan Cheng, Heyong Qin, Peng Zhang. Microstructure evolution and mechanical property characterization of a nickel-based superalloy at the mesoscopic scale[J]. J. Mater. Sci. Technol., 2020, 47: 177-189.

Figures/Tables 18

Table 1 Specific heat treatment process of Inconel 718.

Sample state	Solution treatment	Aging heat treatment
A-1, A-12, A-24	1050 °C × 1 h/WQ	720 °C × 1 h, 12 h, and 24 h/FC at 55 °C/h to 620 °C × 8 h/WQ
B-1, B-12, B-24	1100 °C × 1 h/WQ	720 °C × 1 h, 12 h, and 24 h/FC at 55 °C/h to 620 °C × 8 h/WQ
C-1, C-12, C-24	1150 °C × 1 h/WQ	720 °C × 1 h, 12 h, and 24 h/FC at 55 °C/h to 620 °C × 8 h/WQ
D-1, D-12, D-24	1200 °C × 1 h/WQ	720 °C × 1 h, 12 h, and 24 h/FC at 55 °C/h to 620 °C × 8 h/WQ
E-1, E-12, E-24	1250 °C × 1 h/ WQ	720 °C × 1 h, 12 h, and 24 h/FC at 55 °C/h to 620 °C × 8 h/WQ

Fig. 1. Grain morphologies of Inconel 718 after various solution treatment temperatures: (a) the original sample; (b) 1050 °C; (c) 1100 °C; (d) 1150 °C; (e) 1200 °C; (f) 1250 °C.

Fig. 2. Grain size distribution histograms of specimens at different solution temperatures: (a) 1050 °C; (b) 1100 °C; (c) 1150 °C; (d) 1200 °C; (e) 1250 °C.

Table 2 Grain size and d/t of Inconel 718 after various solution treatment temperatures.

Solution temperature (°C)	d (μm)	t (μm)	d/t
1050	50.6	200	0.253
1100	69.8	200	0.349
1150	91.4	200	0.457
1200	107.4	200	0.537
1250	134.6	200	0.673

Fig. 3. Pole figures of the solution treated samples with various grain sizes.

Fig. 4. Microstructures of γ″ phases obtained by TEM characterization: (a) BF image, (b) HRTEM image, and (c) SAED pattern of γ″ phases in sample state B-1; (d) BF image, (e) HRTEM image, and (f) SAED pattern of γ″ phases in sample state B-12; (g) BF image, (h) HRTEM image, and (i) SAED pattern of γ″ phase in sample state B-24.

Fig. 5. Phase identification of γ″ phases on [001] zone axis of matrix γ phase: (a-d) SAED patterns according to the areas highlighted in Fig. 3(d); (e-h) simulated SAED patterns using the DO22 crystal structure in the orientation as shown below in (i-l).

Fig. 6. Phase identification of γ″ phases with the small sizes: (a) HRTEM image on [001] zone axis of matrix γ phase; (b) FFT images according to the highlighted squares in (a).

Fig. 7. Phase identification of γ′ phases on [001] zone axis of matrix γ phase: (a) HRTEM image; (b) FFT image according to the highlighted squares in (a); (c) simulated SAED pattern using the L12 crystal structure on [001] zone axis of matrix γ phase; (d) the atomic cell structure of γ′ phase.

Fig. 8. Number weighted diameter distributions of γ″ phases: (a) sample state B-1; (b) sample state B-12; (c) sample state B-24; (d) particle size and volume fraction of γ″ phases.

Fig. 9. Engineering stress - engineering strain curves of Inconel 718 with various aging times: (a) 1 h; (b) 12 h; (c) 24 h.

Fig. 10. Mechanical properties of Inconel 718 with various grain sizes and aging times: (a) yield strength; (b) ultimate tensile strength; (c) fracture elongation.

Table 3 Specific mechanical properties of Inconel 718 foils at the mesoscopic scale.

Aging time (h)	d (μm)	σ_s (MPa)	σ_b (MPa)	σ_s/σ_b (%)	ε_f (%)
0	50.6	335 ± 6.1	821 ± 15.4	40.9	52.4 ± 4.3
	69.8	328 ± 6.4	811 ± 10.6	40.4	52.0 ± 2.7
	91.4	316 ± 6.4	797 ± 3.6	39.6	51.4 ± 1.9
	107.4	304 ± 1.4	764 ± 9.0	39.7	49.9 ± 1.5
	134.6	295 ± 5.7	711 ± 15.0	41.5	49.5 ± 1.9
1	50.6	779 ± 4.5	1184 ± 9.1	65.8	34.3 ± 0.8
	69.8	743 ± 27.8	1143 ± 13.3	65.0	31.7 ± 2.3
	91.4	705 ± 6.4	1076 ± 14.1	65.5	31.2 ± 1.7
	107.4	679 ± 6.8	1024 ± 8.0	66.3	30.0 ± 0.7
	134.6	600 ± 11.6	909 ± 13.2	66.0	29.8 ± 0.7
12	50.6	1064 ± 20.6	1382 ± 20.0	77.0	23.8 ± 1.2
	69.8	1028 ± 5.9	1366 ± 10.6	75.3	23.0 ± 2.3
	91.4	1010 ± 8.7	1335 ± 12.7	75.7	19.8 ± 0.6
	107.4	985 ± 10.0	1283 ± 13.9	76.8	17.8 ± 1.3
	134.6	909 ± 15.5	1181 ± 16.9	77.0	16.2 ± 1.8
24	50.6	1124 ± 13.0	1404 ± 11.2	80.1	22.9 ± 0.6
	69.8	1094 ± 2.7	1383 ± 6.8	79.1	21.2 ± 0.5
	91.4	1087 ± 6.0	1370 ± 7.9	79.3	17.1 ± 0.4
	107.4	1072 ± 14.7	1336 ± 16.6	80.2	15.5 ± 0.6
	134.6	1040 ± 13.5	1268 ± 22.0	82.0	11.9 ± 3.0

Fig. 11. Flow stress versus inverse square root of the grain size at different true strains at the mesoscopic scale: (a) aging time of 1 h; (b) aging time of 12 h; (c) aging time of 24 h.

Table 4 The K(ε) values at various true strains in zone A and zone B at different aging times.

Sample state		ε = 0.02	ε = 0.05	ε = 0.10	ε=0.15
1 h	Zone A	7009.60	7799.51	9772.76	9988.15
	Zone B	1912.49	2294.40	2256.88	2910.06
	ΔK(ε)	5097.11	5505.11	7515.88	7078.09
12 h	Zone A	5534.44	6100.07	6558.78	7437.61
	Zone B	1886.42	2092.97	2182.01	2189.94
	ΔK(ε)	3648.02	4007.1	4376.77	5247.67
24 h	Zone A	3633.89	4104.57	4425.35	4836.52
	Zone B	1573.59	1702.45	1733.03	1707.37
	ΔK(ε)	2060.3	2402.12	2692.32	3129.15

Fig. 12. Mechanism diagram of the size effect of Inconel 718.

Table 5 Summary of input data used in the hybrid material constitutive model.

Parameter	M	m	α	G (GPa)	b (nm)	k_s (MPa/at%^2/3)	k	k₃ (MPa)	k₄ (MPa μm^1/2)	n₁	n₂
Value	3.06	2.2	0.3	80	0.248	24.0	1.13	320.8	97.1	0.63	0.62

Fig. 13. Experimental and calculated true stress - true strain curves of Inconel 718: (a, b) aging time of 1 h; (c, d) aging time of 12 h; (e, f) aging time of 24 h.

References 58

[1]	A. Diehl, U. Engel, M. Geiger, Int. J. Adv. Manuf. Technol. 47 (2010) 53-61.
[2]	I. Irthiea, G. Green, S. Hashim, A. Kriama, Int. J. Mach. Tool. Manuf. 76 (2014) 21-33.
[3]	C. Keller, E. Hug, R. Retoux, X. Feaugas, Mech. Mater. 42 (2010) 44-54.
[4]	B. Meng, M.W. Fu, Mater. Des. 83 (2015) 400-412.
[5]	X.X. Chen, A.H.W. Ngan, Scr. Mater. 64 (8) (2011) 717-720.
[6]	S. Wang, L. Niu, C. Chen, Y. Pang, B. Liao, Z.H. Zhong, P. Lu, P. Li, X.D. Wu, J.W. Coenen, L.F. Cao, Y.C. Wu, Mater. Sci. Eng. A 730 (2018) 244-261.
[7]	E. Hug, P.A. Dubos, C. Keller, L. Duchêne, A.M. Habraken, Mech. Mater. 91 (2015) 136-151.
[8]	E. Hug, P.A. Dubos, C. Keller, Mater. Sci. Eng. A 574 (2013) 253-261.
[9]	X.M. Lai, L.F. Peng, P. Hu, S. Lan, J. Ni, Comput. Mater. Sci. 43 (2008) 1003-1009.
[10]	C.J. Wang, H.Y. Wang, F.F. Geng, G. Chen, L. Cui, P. Zhang, Mater. Sci. Eng. A 714 (2018) 14-24.
[11]	P. Páramo-Kañetas, U. Özturk, J. Calvo, J.M. Cabrera, M. Guerrero-Mata, J. Mater. Process. Technol. 255 (2018) 204-211.
[12]	Q. Zhu, G. Chen, C.J. Wang, H.Y. Qin, P. Zhang, Materials 12 (15) (2019) 2461.
[13]	M.S. Chen, Z.H. Zou, Y.C. Lin, H.B. Li, G.Q. Wang, J. Mater. Sci. Technol. 35 (2019) 1403-1411.
[14]	J. Wu, C. Li, Y.C. Liu, Y. Wu, Q. Guo, H. Li, H. Wang, Mater. Sci. Eng. A 743 (2019) 623-635.
[15]	D.G. He, Y.C. Lin, Y. Tang, L. Li, J. Chen, M.S. Chen, X.M. Chen, Mater. Sci. Eng. A 746 (2019) 372-383.
[16]	Q. Zhu, C.J. Wang, H.Y. Qin, G. Chen, P. Zhang, Mater. Charact. 156 (2019), 109875.
[17]	Y.K. Kim, D. Kim, H.K. Kim, E.Y. Yoon, Y. Lee, C.S. Oh, B.J. Lee, Int. J. Plast. 110 (2018) 123-144.
[18]	A.C. Yeh, K.W. Lu, C.M. Kuo, H.Y. Bor, C.N. Wei, Mater. Sci. Eng. A 530 (2011) 525-529.
[19]	A.K. Roy, A. Venkatesh, J. Alloys Compd. 496 (2010) 393-398.
[20]	L.T. Chang, W.R. Sun, Y.Y. Cui, F. Zhang, R. Yang, J. Alloys Compd. 590 (2014) 227-232.
[21]	M. Cheng, H.Y. Zhang, S.H. Zhang, J. Mater. Sci. 47 (2012) 251-256.
[22]	X.M. Zhu, C.Y. Gong, Y.F. Jia, R.Z. Wang, C.C. Zhang, Y. Fu, S.T. Tu, X.C. Zhang, J. Mater. Sci. Technol. 35 (2019) 1607-1617.
[23]	P. Zhao, C. Shen, S.R. Niezgoda, Y. Wang, Int. J. Plast. 109 (2018) 153-168.
[24]	S. Ghorbanpour, M. Zecevic, A. Kumar, M. Jahedi, J. Bicknell, L. Jorgensen, I.J. Beyerlein, M. Knezevic, Int. J. Plast. 99 (2017) 162-185.
[25]	R. Zhao, J.Q. Han, B.B. Liu, M. Wan, Mater. Des. 94 (2016) 195-206.
[26]	R. Zhao, X.J. Li, M. Wan, J.Q. Han, B. Meng, Z.Y. Cai, Mater. Des. 130 (2017) 413-425.
[27]	H.P. Wang, C.H. Zheng, P.F. Zou, S.J. Yang, L. Hu, B. Wei, J. Mater. Sci. Technol. 34 (2018) 436-439.
[28]	S. Sui, J. Chen, L. Ma, W. Fan, H. Tan, F. Liu, X. Lin, J. Alloys Compd. 770 (2019) 125-135.
[29]	H.J. Zhang, C. Li, Y.C. Liu, Q. Guo, Y. Huang, H. Li, J. Yu, J. Alloys Compd. 716 (2017) 65-72.
[30]	J.W. Brooks, P.J. Bridges, Superalloys 88 (1988) 33-42.
[31]	Y. Mei, Y. Liu, C. Liu, C. Li, L. Yu, Q. Guo, H. Li, J. Alloys Compd. 649 (2015) 949-960.
[32]	A. Drexler, B. Oberwinkler, S. Primig, C. Turk, E. Povoden-Karadeniz, A. Heinemann, W. Ecker, M. Stockinger, Mater. Sci. Eng. A 723 (2018) 314-323.
[33]	P. Stadelmann, Microsc. Microanal. 9 (S03) (2003) 60-61.
[34]	R. Lawitzki, S. Hassan, L. Karge, J. Wagner, D. Wang, J. von Kobylinski, C. Krempaszky, M. Hofmann, R. Gilles, G. Schmitz, Acta Mater. 163 (2019) 28-39.
[35]	R. Shi, D.P. McAllister, N. Zhou, A.J. Detor, R. DiDomizio, M.J. Mills, Y. Wang, Acta Mater. 164 (2019) 220-236.
[36]	A.J. Detor, R. DiDomizio, R. Sharghi-Moshtaghin, N. Zhou, R. Shi, Y. Wang, D.P. McAllister, M.J. Mills, Metall. Mater. Trans. A 49 (2018) 708-717.
[37]	M.K. Miller, Micron 32 (2001) 757-764.
[38]	M. Sundararaman, P. Mukhopadhyay, S. Banerjee, Metall. Trans. A 23 (1992) 2015-2028.
[39]	M. Sundararaman, P. Mukhopadhyay, Mater. Charact. 31 (1993) 191-196.
[40]	R. Cozar, A. Pineau, Metall. Mater. Trans. B 4 (1973) 47-59.
[41]	D. Del Genovese, J. Rösler, P. Strunz, D. Mukherji, R. Gilles, Metall. Mater. Trans. A 36 (2005) 3439-3450.
[42]	D.F. Paulonis, J.M. Oblak, D.S. Duvall, Trans ASM 62 (1969) 611-622.
[43]	Y.F. Han, P. Deb, M.C. Chaturvedi, Met. Sci. 16 (1982) 555-562.
[44]	S. Sui, H. Tan, J. Chen, C. Zhong, Z. Li, W. Fan, A. Gasser, W. Huang, Acta Mater. 164 (2019) 413-427.
[45]	C. Slama, M. Abdellaoui, J. Alloys Compd. 306 (2000) 277-284.
[46]	A. Devaux, L. Nazé, R. Molins, A. Pineau, A. Organista, J.Y. Guédou, J.F. Uginet, P. Héritier, Mater. Sci. Eng. A 486 (2008) 117-122. DOI URL
[47]	M. Geiger, M. Kleiner, R. Eckstein, Ann. CIRP 50 (2001) 445-462.
[48]	H. Mecking, U.F. Kocks, Acta Metall. 29 (1981) 1865-1875.
[49]	R.W. Armstrong, J. Mech, Phys. Solids 9 (1961) 196-199.
[50]	E.I. Galindo-Nava, L.D. Connor, C.M.F. Rae, Acta Mater. 98 (2015) 377-390.
[51]	S. Schänzer, E. Nembach, Acta Metall. Mater. 40 (1992) 803-813.
[52]	C. Joseph, C. Persson, M.H. Colliander, Mater. Sci. Eng. A 679 (2017) 520-530.
[53]	S.K. Shaha, F. Czerwinski, W. Kasprzak, D.L. Chen, J. Alloys Compd. 593 (2014) 290-299.
[54]	A. Simar, Y. Bréchet, B. de Meester, A. Denquin, T. Pardoen, Acta Mater. 55 (2007) 6133-6143.
[55]	V.M.J. Sharma, K.S. Kumar, B.N. Rao, S.D. Pathak, Mater. Sci. Eng. A 502 (2009) 45-53.
[56]	L.M. Cheng, W.J. Poole, J.D. Embury, D.J. Lloyd, Metall. Mater. Trans. A 34 (2003) 2473-2481.
[57]	G. Chen, C. Yi, F.F. Xu, Y. Zhang, P. Zhang, C.J. Wang, Mater. Sci. Eng. A 730 (2018) 207-216.
[58]	G.Y. Kim, J. Ni, M. Koç, J. Manuf. Sci. Eng. 129 (2007) 470-476.