Effects of Chromium on the Microstructures and Mechanical Properties of AlCoCrxFeNi2.1 Eutectic High Entropy Alloys

doi:10.1007/s40195-021-01303-4

Abstract

Abstract:

In the present study, a series of AlCoCr_xFeNi_2.1 (x = 0, 0.25, 0.5, 0.75, 1.0) eutectic high entropy alloys (EHEAs) have been designed and prepared. And the effect of Cr content on the microstructures and mechanical properties of the AlCoCr_xFeNi_2.1 alloys was systematically investigated. The results indicate that the AlCoCr_xFeNi_2.1 (x > 0) alloys exhibit almost complete lamellar eutectic microstructures with a mixture structure of FCC and B2 phases. And the AlCoFeNi_2.1 alloy without Cr element exhibited a hypoeutectic microstructure with a primary B2 phase. In addition, the eutectic microstructures for AlCoCr_xFeNi_2.1 eutectic alloys do not change significantly. The room temperature compressive tests results show that with an increase in Cr content (from x = 0 to x = 1.0), the yield strength will first decrease, and thereafter increase. The trend is the opposite with the fracture strength and plastic strain. They show an increase trend at first, and then decrease. The AlCoCr_0.5FeNi_2.1 (Cr0.5) alloy shows the best comprehensive mechanical properties. The tensile yield strength, fracture strength, and elongation are 536.5 MPa, 1062 MPa, and 13.8%, respectively. Furthermore, the Cr0.5 alloy also displays a high strength with a yield strength of 362 MPa at 700 ºC. In summary, by changing the Cr content, AlCoCr_xFeNi_2.1 eutectic high entropy alloys with excellent comprehensive mechanical properties were obtained and prepared.

Key words: Eutectic, High entropy alloy, Compressive properties, Tensile strength

Hui Jiang, Li Li, Rui Wang, Kaiming Han, Quanwei Wang. Effects of Chromium on the Microstructures and Mechanical Properties of AlCoCr_xFeNi_2.1 Eutectic High Entropy Alloys[J]. Acta Metallurgica Sinica (English Letters), 2021, 34(11): 1565-1573.

Figures/Tables 12

Fig. 1 Low-magnification SEM images of as-cast AlCoCrxFeNi2.1 alloys: a x = 0, b x = 0.25, c x = 0.5, d x = 0.75, e x = 1.0

Fig. 2 High-magnification SEM images of as-cast AlCoCrxFeNi2.1 alloys: a x = 0, b x = 0.25, c x = 0.5, d x = 0.75, e x = 1.0

Table 1 Chemical compositions of different regions in the AlCoCrxFeNi2.1 alloy by EDS (at.%)

Alloy	Regions		Al	Co	Fe	Ni	Cr
0		α	25.01	17.48	16.62	40.89	-
	E	A	14.29	21.95	23.61	40.14	-
	E	B	26.55	16.34	14.52	42.59	-
0.25	E	A	15.81	20.98	20.25	37.28	5.69
0.25	E	B	30.76	14.32	13.66	38.63	2.63
0.5	E	A	14.28	19.48	21.71	32.79	11.74
0.5	E	B	31.55	14.1	12.48	37.61	4.26
0.75	E	A	14.01	18.6	19.71	32.82	14.86
0.75	E	B	30.83	13.09	11.09	38.63	6.35
1.0	E	A	11.69	18.03	19.39	31.64	19.25
1.0	E	B	31.62	12.14	10.04	38.53	7.67

Fig. 3 X-ray diffraction patterns of the AlCoCrxFeNi2.1 HEAs

Fig. 4 DSC curves of the AlCoCr0.5FeNi2.1EHEA

Fig. 5 Compressive engineering stress-strain curves of the AlCoCrxFeNi2.1 HEAs at room temperature

Table 2 Compressive properties of AlCoCrxFeNi2.1 HEAs

Alloys	Yield strength σ_y (MPa)	Compressive strength σ_max (MPa)	Plastic strain ε_p (%)
Cr0	726	2768	37.9
Cr0.25	617	3161	47.5
Cr0.5	617	3167	47.6
Cr0.75	643	3072	46.9
Cr1.0	650	2085	37.5

Fig. 6 Compressive engineering stress-strain curves of the AlCoCr0.5FeNi2.1 HEA at high temperature

Table 3 High temperature compressive properties of AlCoCr0.5FeNi2.1 HEAs

Temperature (°C)	Yield strength	Maximum strength	Fracture strain
Temperature (°C)	σ_y (MPa)	σ_max (MPa)	ε (%)
700	362	461	20
800	170	190	80
900	85	98	80

Fig. 7 Tensile stress-strain curve of as-cast AlCoCr0.5FeNi2.1EHEA at room temperature

Fig. 8 EM images of tensile fracture surface of AlCoCr0.5FeNi2.1 EHEA: a low magnification; b high magnification

Fig. 9 TEM images of tensile fracture surface of AlCoCr0.5FeNi2.1 EHEA: a low magnification of two phases; b,c SADPs of the FCC/L12 and B2 phases; d, e high magnification of FCC (L12) phase

References 34

[1]	Y.P. Lu, Y. Dong, S. Guo, L. Jiang, H.J. Kang, T.M. Wang, B. Wen, Z.J. Wang, J.C. Jie, Z.Q. Cao, H.H. Ruan, T.J. Li, Sci. Rep. 4, 6200 (2014) DOI URL
[2]	Y. Dong, L. Jiang, H. Jiang, Y. Lu, T. Wang, T. Li, Mater. Des. 82, 91 (2015) DOI URL
[3]	F. He, Z. Wang, X. Shang, C. Leng, J. Li, J. Wang, Mater. Des. 104, 259 (2016) DOI URL
[4]	Ł Rogal, J. Morgiel, Z. Świątek, F. Czerwiński, Mater. Sci. Eng. A 651, 590 (2016) DOI URL
[5]	Y.P. Lu, X.Z. Gao, L. Jiang, Z.N. Chen, T.M. Wang, J.C. Jie, H.J. Kang, Y.B. Zhang, S. Guo, H.H. Ruan, Y.H. Zhao, Z.Q. Cao, T.J. Li, Acta Mater. 124, 143 (2017) DOI URL
[6]	X. Jin, Y. Zhou, L. Zhang, X.Y. Du, B.S. Li, Mater. Lett. 216, 144 (2018) DOI URL
[7]	H. Jiang, D.X. Qiao, Y.P. Lu, Z. Ren, Z.Q. Cao, T.M. Wang, T.J. Li, Scr. Mater. 165, 145 (2019) DOI URL
[8]	Q.F. Wu, Z.J. Wang, T. Zheng, C. Da, Z.S. Yang, J.J. Li, J.J. Kai, J.C. Wang, Mater. Lett. 253, 268 (2019) DOI URL
[9]	L. Wang, X. Wu, C. Yao, J. Shen, Y. Zhang, Y. Ge, G. Zhang, Metall. Mater. Trans. A 51, 5781 (2020) DOI URL
[10]	H. Jiang, D. Qiao, W. Jiao, K. Han, L. Yiping, P.K. Liaw, J. Mater. Sci. Technol. 61, 119 (2021) DOI
[11]	I.S. Wani, T. Bhattacharjee, S. Sheikh, Y.P. Lu, S. Chatterjee, P.P. Bhattacharjee, S. Guo, N. Tsuji, Mater. Res. Lett. 4, 174 (2016) DOI URL
[12]	I.S. Wani, T. Bhattacharjee, S. Sheikh, I.T. Clark, M.H. Park, T. Okawa, S. Guo, P.P. Bhattacharjee, N. Tsuji, Intermetallics 84, 42 (2017) DOI URL
[13]	T. Wang, M. Komarasamy, S. Shukla, R.S. Mishra, J. Alloys Compd. 766, 312 (2018) DOI URL
[14]	P. Li, H. Sun, S. Wang, X. Hao, H. Dong, J. Alloys Compd. 814, 152322 (2020) DOI URL
[15]	R. John, A. Karati, J. Joseph, D. Fabijanic, B.S. Murty, J. Alloys Compd. 835, 155424 (2020) DOI URL
[16]	M.H. Asoushe, A.Z. Hanzaki, H.R. Abedi, B. Mirshekari, T. Wegener, S.V. Sajadifar, T. Niendorf, Mater. Sci. Eng. A 799, 140012 (2021) DOI URL
[17]	S.R. Reddy, S. Yoshida, U. Sunkari, A. Lozinko, J. Joseph, R. Saha, D. Fabijanic, S. Guo, P.P. Bhattacharjee, N. Tsuji, Mater. Sci. Eng. A 764, 138226 (2019) DOI URL
[18]	M.J. Kim, G.C. Kang, S.H. Hong, H.J. Park, S.C. Mun, G. Song, K.B. Kim, J. Mater. Sci. Technol. 57, 131 (2020) DOI URL
[19]	Y. Dong, Z. Yao, X. Huang, F. Du, C. Li, A. Chen, F. Wu, Y. Cheng, Z. Zhang, J. Alloys Compd. 823, 153886 (2020) DOI URL
[20]	F. Meng, S.F. Bauer, Y. Liao, I. Baker, Intermet. 56, 28 (2015) DOI URL
[21]	L.Y. Sheng, J.T. Guo, H.Q. Ye, Mater. Des. 30, 964 (2009) DOI URL
[22]	F. Meng, J. Qiu, I. Baker, Mater. Sci. Eng. A 586, 45 (2013) DOI URL
[23]	C.G. Mckamey, C.T. Liu, J. Mater. Res. 24, 1156 (1989) DOI URL
[24]	C.G. Mckamey, Scr. Metall. Mater. 24, 2119 (1990) DOI URL
[25]	Y.Y. Liao, I. Baker, Mater. Sci. Eng. A 528, 3998 (2011) DOI URL
[26]	M. Zamanzade, H. Vehoff, A. Barnoush, Acta Mater. 69, 210 (2014) DOI URL
[27]	E. Hamzah, M. Kanniah, M. Harun, J. Mater. Sci. 42, 9063 (2007) DOI URL
[28]	I. Baker, Mater. Sci. Eng. A 192, 1 (1995)
[29]	Y. Liao, I. Baker, J. Mater. Sci. 46, 2009 (2011) DOI URL
[30]	X.Z. Gao, Y.P. Lu, B. Zhang, N.N. Liang, G.Z. Wu, G. Sha, J.Z. Liu, Y.H. Zhao, Acta Mater. 141, 59 (2017) DOI URL
[31]	A. Akhtar, E. Teghtsoonian, Philos. Mag. 25, 897 (1972) DOI URL
[32]	N.D.O.P. Modi, D.P. Mondal, A.K. Jha, A.H. Yegneswaran, H.K. Khaira, Mater. Charact. 46, 347 (2004) DOI URL
[33]	I.M.B.M. Dollar, A.W. Thompson, Acta Metall. 36, 311 (1988) DOI URL
[34]	N.P.L.L.I. Gladshtein, B.F. Belyaev, Metallurgist 56, 579 (2012) DOI URL