Heterogeneous Structure Design to Strengthen Carbon-Containing CoCrFeNi High Entropy Alloy

doi:10.1007/s40195-021-01268-4

Abstract

Abstract:

A carbon-containing CoCrFeNi high entropy alloy (HEA) with heterogeneous structures was obtained through thermomechanical treatments, which induced concurrent recrystallization and carbide precipitation in the alloy. A combination of high yield strength (556 MPa) and large uniform elongation (45%) was achieved in the investigated alloy. The enhancement of the strength is attributed to the combined effects of grain refinement, precipitation strengthening and microstructural heterogeneity. Our work demonstrated that the heterogeneity design could be realized by thermomechanical processes, which provided a practical strategy for producing HEAs with high performance.

Key words: High entropy alloy, Heterogeneous structures, Mechanical properties, Interstitial

Xiaomeng Qin, Chan Hung Shek. Heterogeneous Structure Design to Strengthen Carbon-Containing CoCrFeNi High Entropy Alloy[J]. Acta Metallurgica Sinica (English Letters), 2021, 34(11): 1503-1510.

Figures/Tables 8

Table 1 Chemical composition of the investigated high entropy alloy (at.%)

	Cr	Fe	Co	Ni	C
Nominal composition	24.85	24.85	24.85	24.85	0.60
Measured composition	25.48	24.34	24.68	24.94	0.56

Fig. 1 Schematic diagram of the thermomechanical treatment for the annealed HEA

Fig. 2 a-c Microstructures of the as-cast HEA: a EBSD band contrast image; b EBSD inverse pole figure (IPF) map; c TEM bright-field image and the corresponding SAED patterns. d XRD patterns of the as-cast and annealed alloys

Fig. 3 Microstructures of the annealed HEA via (a-e) EBSD and f-g SEM: a forward scatter detector figure; b band contrast image; c IPF map; d grain size distribution; e enlarged view of region E in (b); f SEM image showing the distribution of precipitates and g the corresponding EDS elemental maps. RD is corresponding to the cold-rolling direction

Fig. 4 TEM /HRTEM /STEM micrographs of the annealed HEA: a, b TEM images showing the morphologies of precipitates and fine grains; c corresponding SAED patterns of the matrix (Region A in (a)); d TEM image and corresponding SAED patterns of the tiny precipitates (Region C in (d)); e HRTEM micrograph of the tiny precipitates; f corresponding SAED pattern of the coarse precipitates (Region B in (b)); g STEM mapping of the tiny precipitates. Coarse and tiny precipitates are marked by arrows and circles, respectively

Fig. 5 Mechanical behaviors of the as-cast and annealed carbon-containing HEAs: a engineering stress-strain curves; b LUR stress-strain curves; c enlarged Hysteresis loops; d estimated back stress versus true strain

Table 2 Parameters for calculating the yield strength increment in Eqs. (2) and (3)

Alloy	Lattice constant	Average grain	Carbides fraction (%)		Carbides diameter (nm)
Alloy	a₀ (Å)	size (μm)	Coarse	Tiny	Coarse	Tiny
As-cast	3.573	63.1	-	-		-
Annealed	3.569	1.4	4.7	1	600	50

Fig. 6 Microstructural characterization of the carbon-containing HEAs after tensile tests: a fractured tensile specimens; b,c fracture morphology of the investigated alloys; d sample surface of the as-cast alloy showing the slip bands; e IPF map and f GOS map of the sample surface of the annealed alloy by EBSD; g bright-field TEM image and corresponding SAED patterns (the inset) showing the substructures of the as-cast alloy (diffraction spots circled in yellow corresponding to the deformation twins); h,i bright-field TEM images showing the substructures and carbides in the annealed alloy. GB, DTs and DCs are corresponding to grain boundary, deformation twins and dislocation cells, respectively. Coarse and tiny precipitates are marked by red arrows and circles, respectively

References 39

[1]	B. Cantor, I.T.H. Chang, P. Knight, A.J.B. Vincent, Mater. Sci. Eng. A 375, 213 (2004)
[2]	J.W. Yeh, S.K. Chen, S.J. Lin, J.Y. Gan, T.S. Chin, T.T. Shun, C.H. Tsau, S.Y. Chang, Adv. Eng. Mater. 6, 299 (2004) DOI URL
[3]	M.H. Chuang, M.H. Tsai, W.R. Wang, S.J. Lin, J.W. Yeh, Acta Mater. 59, 6308 (2011) DOI URL
[4]	C.E. Slone, J. Miao, E.P. George, M.J. Mills, Acta Mater. 165, 496 (2019) DOI
[5]	J.Y. He, H. Wang, H.L. Huang, X.D. Xu, M.W. Chen, Y. Wu, X.J. Liu, T.G. Nieh, K. An, Z.P. Lu, Acta Mater. 102, 187 (2016) DOI URL
[6]	B. Gorr, M. Azim, H.J. Christ, T. Mueller, D. Schliephake, M. Heilmaier, J. Alloys Compd. 624, 270 (2015) DOI URL
[7]	M. Zhang, Y. Ma, W. Dong, X. Liu, Y. Lu, Y. Zhang, R. Li, Y. Wang, P. Yu, Y. Gao, G. Li, Mater. Sci. Eng. A 771, 138566 (2020) DOI URL
[8]	S. Yoshida, T. Ikeuchi, T. Bhattacharjee, Y. Bai, A. Shibata, N. Tsuji, Acta Mater. 171, 201 (2019) DOI
[9]	Z. Wu, H. Bei, G.M. Pharr, E.P. George, Acta Mater. 81, 428 (2014) DOI URL
[10]	B. Gludovatz, A. Hohenwarter, D. Catoor, E.H. Chang, E.P. George, R.O. Ritchie, Science 345, 1153 (2014) DOI PMID
[11]	Z. Wu, H. Bei, F. Otto, G.M. Pharr, E.P. George, Intermetallics 46, 131 (2014) DOI URL
[12]	D.B. Miracle, O.N. Senkov, Acta Mater. 122, 448 (2017) DOI URL
[13]	F. Otto, A. Dlouhý, C. Somsen, H. Bei, G. Eggeler, E.P. George, Acta Mater. 61, 5743 (2013) DOI URL
[14]	H. Shahmir, J. He, Z. Lu, M. Kawasaki, T.G. Langdon, Mater. Sci. Eng. A 676, 294 (2016) DOI URL
[15]	T. Yang, Y. Zhao, Y. Tong, Z. Jiao, J. Wei, J. Cai, X. Han, D. Chen, A. Hu, J. Kai, Science 362, 933 (2018) DOI PMID
[16]	J.Y. He, H. Wang, Y. Wu, X.J. Liu, H.H. Mao, T.G. Nieh, Z.P. Lu, Intermetallics 79, 41 (2016) DOI URL
[17]	B. Gwalani, V. Soni, M. Lee, S.A. Mantri, Y. Ren, R. Banerjee, Mater. Des. 121, 254 (2017) DOI URL
[18]	Y. Tong, D. Chen, B. Han, J. Wang, R. Feng, T. Yang, C. Zhao, Y.L. Zhao, W. Guo, Y. Shimizu, C.T. Liu, P.K. Liaw, K. Inoue, Y. Nagai, A. Hu, J.J. Kai, Acta Mater. 165, 228 (2019) DOI
[19]	N. Li, C.L. Jia, Z.W. Wang, L.H. Wu, D.R. Ni, Z.K. Li, H.M. Fu, P. Xue, B.L. Xiao, Z.Y. Ma, Acta Metall. Sin.-Engl. Lett. 33, 947 (2020)
[20]	I. Ondicho, B. Alunda, D. Owino, L. Otieno, M. Chepkoech, Acta Metall. Sin.-Engl. Lett. 33, 1159 (2020)
[21]	M. Yang, D. Yan, F. Yuan, P. Jiang, E. Ma, X. Wu, Proc. Nat. Acad. Sci. 115, 7224 (2018) DOI URL
[22]	T. Xiong, S. Zheng, J. Pang, X. Ma, Scr. Mater. 186, 336 (2020) DOI URL
[23]	S.W. Wu, G. Wang, Q. Wang, Y.D. Jia, J. Yi, Q.J. Zhai, J.B. Liu, B.A. Sun, H.J. Chu, J. Shen, P.K. Liaw, C.T. Liu, T.Y. Zhang, Acta Mater. 165, 444 (2019) DOI
[24]	M. Song, R. Zhou, J. Gu, Z.W. Wang, S. Ni, Y. Liu, Appl. Mater. Today 18, 6 (2020)
[25]	R.B. Chang, W. Fang, H.Y. Yu, X. Bai, X. Zhang, B.X. Liu, F.X. Yin, Scr. Mater. 172, 144 (2019) DOI URL
[26]	M. Klimova, D. Shaysultanov, A. Semenyuk, S. Zherebtsov, N. Stepanov, J. Alloys Compd. 851, 14 (2021)
[27]	F. Humphreys, P. Kalu, Acta Metall. 35, 2815 (1987) DOI URL
[28]	Y.T. Wang, J.B. Li, Y.C. Xin, X.H. Chen, M. Rashad, B. Liu, Y. Liu, Acta Metall. Sin.-Engl. Lett. 32, 932 (2019)
[29]	M.V. Klimova, D.G. Shaysultanov, R.S. Chernichenko, V.N. Sanin, N.D. Stepanov, S.V. Zherebtsov, A.N. Belyakov, Mater. Sci. Eng. A 740, 201 (2019)
[30]	T. Gladman, Mater. Sci. Technol. 15, 30 (1999) DOI URL
[31]	X. Wu, M. Yang, F. Yuan, G. Wu, Y. Wei, X. Huang, Y. Zhu, Proc. Nat. Acad. Sci. 112, 14501 (2015) DOI URL
[32]	X. Wu, Y. Zhu, Mater. Res. Lett. 5, 527 (2017) DOI URL
[33]	F.L. Jiang, C.C. Zhao, D.S. Liang, W.W. Zhu, Y.W. Zhang, S. Pan, F.Z. Ren, Mater. Sci. Eng. A 771, 6 (2020)
[34]	M. Yang, Y. Pan, F. Yuan, Y. Zhu, X. Wu, Mater. Res. Lett. 4, 145 (2016) DOI URL
[35]	E. Ma, T. Zhu, Mater. Today 20, 323 (2017) DOI URL
[36]	A.V. Panin, M.S. Kazachenok, A.I. Kozelskaya, R.R. Hairullin, E.A. Sinyakova, Mater. Sci. Eng. A 647, 43 (2015) DOI URL
[37]	M.R. Stoudt, J.B. Hubbard, Acta Mater. 53, 4293 (2005) DOI URL
[38]	M.R. Stoudt, L.E. Levine, A. Creuziger, J.B. Hubbard, Mater. Sci. Eng. A 530, 107 (2011) DOI URL
[39]	K. Lu, L. Lu, S. Suresh, Science 324, 349 (2009) DOI PMID