Simultaneously Enhanced Strength and Fracture Resistance in HfNbTaTiZr Refractory High-Entropy Alloy at Higher Strain Rate

doi:10.1007/s40195-025-01826-0

Abstract

Abstract:

The effects of strain rate on tensile properties and fracture behavior of HfNbTaTiZr refractory high-entropy alloy (RHEA) were investigated. With the increase of strain rate in the range from 0.0001 to 0.1 s⁻¹, the yield strength increases from 740 to 825 MPa, demonstrating a strain rate sensitivity coefficient of 0.0173. Notably, while the uniform elongation diminished with rising strain rates, the fracture elongation of the RHEA remained constant at ~ 43%, suggesting an enhanced non-uniform elongation and an improved resistance to tensile fracture. Single-edge notch tension test further proves that the notch toughness increases at elevated loading rates. The complete work-hardening rate curves were plotted, and the work-hardening ability of the RHEA was found not decreasing significantly after necking, especially at high strain rate. The fracture of tensile samples across all the strain rates was dominated by void growth and coalesce, with dimples on the fracture surface being smaller at higher strain rates. This work reveals an unconventional increase in fracture resistance at higher strain rates, further indicating that ductile RHEAs may possess superior potential for use in structural applications subjected to high strain rate loading.

Key words: Refractory high-entropy alloy, HfNbTaTiZr, Strain rate sensitivity, Tensile property, Notch toughness

Hong Chen, Ruitao Qu, Haotian Ma, Kexing Song, Feng Liu. Simultaneously Enhanced Strength and Fracture Resistance in HfNbTaTiZr Refractory High-Entropy Alloy at Higher Strain Rate[J]. Acta Metallurgica Sinica (English Letters), 2025, 38(4): 529-541.

Figures/Tables 10

Fig. 1 Microstructural characterizations of the present HfNbTaTiZr alloy: a EBSD-IPF micrograph; b distribution of area-weighted grain size; c X-ray diffraction pattern; d-h X-ray energy-dispersive spectroscopy (EDS) mappings

Fig. 2 Tensile stress-strain curves and properties of the HfNbTaTiZr RHEA at different strain rates: a typical engineering stress-strain curves, b true stress-true strain curves, c strengths as a function of strain rate, d elongations at different strain rates

Fig. 3Typi cal load-displacement curves of HfNbTaTiZr RHEA under SENT with different loading rates of 0.3 mm/s and 0.0003 mm/s

Fig. 4 True stress-strain curves and work-hardening rate curves of HfNbTaTiZr RHEA at different strain rates: a curves plotted according to the traditional method with the true strain and true strain calculated according to Eqs. (3)-(5); b curves plotted according to Eqs. (6)-(10), which include the Bridgman’s correction for equivalent true stress in the necking region

Fig. 5 a-c Comparisons of engineering stress-strain curves between FE simulation and experiments and d-f stress contours of the axial stress on the longitudinal central sections at different strain rates

Fig. 6 Deformation features of the alloy after tension in different strain rates: a-d 0.001 s−1, e, f 0.1 s−1. a, b SEM images on the side surface of the sample after fracture at the position far away from the fracture surface a and near the fracture surface b. c, e EBSD-IPF map; d, f KAM map. Inset of c shows the distribution of misorientation along the distance along the white arrow in c across several kink bands

Fig. 7 Fracture morphologies of HfNbTaTiZr RHEA after uniaxial tension a-h and SENT i-p. a-d Fracture surfaces of uniaxial tensile samples under different strain rates of a 0.1 s−1, b 0.01 s−1, c 0.001 s−1, d 0.0001 s−1. e-h High magnification images of local positions in a-d, respectively. i-p Fracture surface morphologies of SENT samples at the loading rates of i-l 0.3 mm/s, m-p 0.0003 mm/s

Table 1 Strain rate sensitivity coefficient (m) of various HEAs at room temperature. Here “IM” stands for intermetallic phase

Material	Phase	Strain rate (s⁻¹)	Loading mode	m	References
TiZrHfNbTaMo_0.25	BCC	10^-4-10^-2	Compression	0.0150	[37]
TiZrHfNbTaMo_0.25	BCC	2100-6000	Compression	0.0570
TiZrHfNbTaMo_0.75	BCC	10^-4-10^-2	Compression	0.0110
TiZrHfNbTaMo_0.75	BCC	2100-6000	Compression	0.0720
VNbTa	BCC	10^-2-10^-3	Compression	0.0111	[30]
VNbTa	BCC	2000-5000	Compression	0.2990	[30]
Al_0.1CrFeCoNi	FCC	10^-3-10^-1	Compression	0.0158	[38]
Al_0.1CrFeCoNi	FCC	1000-2600	Compression	0.1040	[38]
CrMnFeCoNi	FCC	1200-2700	Compression	0.1600	[39]
Al_0.4CrMnFeCoNi	FCC	10^-3-10^-1	Compression	0.0389	[40]
Al_0.4CrMnFeCoNi	FCC	250-1300	Compression	0.0480	[40]
NiCoFeCrMo₄W₃	FCC	10^-4-10^-2	Compression	0.0166	[41]
NiCoFeCrMo₄W₃	FCC	3000-4500	Compression	0.2240
NiCoFeCrW₉	FCC + IM	10^-4-10^-2	Compression	0.0077
NiCoFeCrW₉	FCC + IM	3000-4500	Compression	0.2930
HfNbTaTiZr	BCC	2100-3450	Compression	0.0850	[36]
HfNbTaTiZr	BCC	10^-4-10^-1	Tension	0.0173	This work

Fig. 8 Yield strength as a function of strain rate for various HEAs at room temperature. The values of SRS coefficient (m) were added near the data points, which were plotted based on the data in Table 1

Fig. 9 Size of the largest dimple measured on the fracture surfaces of uniaxial tension samples as a function of loading time. The size was determined based on the equivalent diameter of the largest dimple on the fracture surface

References 50

[1]	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)
[2]	Y.F. Ye, Q. Wang, J. Lu, C.T. Liu, Y. Yang, Mater. Today 19, 349 (2016)
[3]	X. Huang, R. Qu, F. Ren, C. Guo, Y. Xing, H. Ma, Y. Lin, J. Liu, K. Song, F. Liu, J. Mater. Res. Technol. 31, 506 (2024)
[4]	Y. Zhou, S. Peng, Y. Guo, X. Wu, C. Liu, Z. Li, Acta Metall. Sin.-Engl. Lett. 37, 1186 (2024)
[5]	H. Yan, Y.A. Zhang, W. Xiao, B. Xue, R. Liu, X. Li, Z. Li, B. Xiong, Acta Metall. Sin.-Engl. Lett. 37, 1480 (2024)
[6]	S.Y. Peng, Y.Z. Tian, Z.Y. Ni, S. Lu, S. Li, Int. J. Plast. 182, 104129 (2024)
[7]	R. Qu, S. Wu, C.A. Volkert, Z. Zhang, F. Liu, Mater. Sci. Eng. A 867, 144729 (2023)
[8]	X. Liu, K. Song, Z. Kou, J. Gong, X. Chen, Q. Gao, H. Sun, P. Liu, R. Qu, L. Hu, Z. Zhang, P. Ramasamy, Z. Liu, Z. Zhang, F. Liu, Z. Zhang, J. Eckert, Int. J. Plast. 177, 103992 (2024)
[9]	B. Gludovatz, A. Hohenwarter, D. Catoor, E.H. Chang, E.P. George, R.O. Ritchie, Science 345, 1153 (2014)
[10]	X. Fan, R. Qu, Z. Zhang, Acta Metall. Sin.-Engl. Lett. 34, 1461 (2021)
[11]	O.N. Senkov, G.B. Wilks, J.M. Scott, D.B. Miracle, Intermetallics 19, 698 (2011)
[12]	C. Rong, J. Yang, X. Zhao, K. Huang, Y. Liu, X. Wang, D. Zhu, R. Chen, Acta Metall. Sin.-Engl. Lett. 37, 633 (2024)
[13]	O.N. Senkov, J.M. Scott, S.V. Senkova, F. Meisenkothen, D.B. Miracle, C.F. Woodward, J. Mater. Sci. 47, 4062 (2012)
[14]	O.N. Senkov, J.M. Scott, S.V. Senkova, D.B. Miracle, C.F. Woodward, J. Alloys Compd. 509, 6043 (2011)
[15]	X.J. Fan, R.T. Qu, Z.F. Zhang, J. Mater. Sci. Technol. 123, 70 (2022)
[16]	Z.C. Meng, K.G. Wang, T. Ali, D. Li, C.G. Bai, D.S. Xu, S.J. Li, A.H. Feng, G.J. Cao, J.H. Yao, Q.B. Fan, H. Wang, R. Yang, Acta Metall. Sin.-Engl. Lett. 37, 1590 (2024)
[17]	L. Liu, Z. Zhou, J. Yu, X. Wang, C. Cui, R. Zhang, Y. Zhou, X. Sun, Acta Metall. Sin.-Engl. Lett. 37, 1453 (2024)
[18]	H.Z. Jiang, Z.Y. Li, T. Feng, P.Y. Wu, Q.S. Chen, S.K. Yao, J.Y. Hou, Acta Metall. Sin.-Engl. Lett. 35, 773 (2022)
[19]	S. Chen, W. Li, F. Meng, Y. Tong, H. Zhang, K.K. Tseng, J.W. Yeh, Y. Ren, F. Xu, Z. Wu, P.K. Liaw, Scr. Mater. 200, 113919 (2021)
[20]	R.R. Eleti, T. Bhattacharjee, A. Shibata, N. Tsuji, Acta Mater. 171, 132 (2019)
[21]	M.L. Hu, W.D. Song, D.B. Duan, Y. Wu, Int. J. Mech. Sci. 182, 105738 (2020)
[22]	L.H. Mills, M.G. Emigh, C.H. Frey, N.R. Philips, S.P. Murray, J. Shin, D.S. Gianola, T.M. Pollock, Acta Mater. 245, 118618 (2023)
[23]	R.Q. Liang, A.S. Khan, Int. J. Plast. 15, 963 (1999)
[24]	W. Chen, Z. Liu, J. Ketkaew, R.M.O. Mota, S.H. Kim, M. Power, W. Samela, J. Schroers, Acta Mater. 107, 220 (2016)
[25]	Z. Zhang, Z. Qu, L. Xu, R. Liu, P. Zhang, Z. Zhang, T.G. Langdon, Acta Mater. 231, 117877 (2022)
[26]	J.M. Choung, S.R. Cho, J. Mater. Sci. Technol. 22, 1039 (2008)
[27]	Z.L. Zhang, M. Hauge, J. Odegård, C. Thaulow, Int. J. Solids Struct. 36, 3497 (1999)
[28]	N.E. Dowling, Mater. Today 8, 83 (2005)
[29]	A. Weck, D.S. Wilkinson, E. Maire, H. Toda, Acta Mater. 56, 2919 (2008)
[30]	G. Yang, Z. Han, J. Yang, Y. Tian, A. Tian, J. Zhang, G. Liu, R. Wei, G. Zhang, Mater. Charact. 213, 114036 (2024)
[31]	S.J. Wu, R.T. Qu, Z.C. Liu, H.F. Li, X.D. Wang, C.W. Tan, P. Zhang, Z.F. Zhang, Int. J. Impact Eng. 152, 103856 (2021)
[32]	Y.L. Bai, Adiabatic Shear Localization: Frontiers and Advances, 2nd edn. (Elsevier Science, Burlington, 2012), p.468
[33]	D. Odoh, G. Owolabi, A. Odeshi, H. Whitworth, Acta Metall. Sin.-Engl. Lett. 26, 378 (2013)
[34]	I. Dowding, C.A. Schuh, Nature 630, 91 (2024)
[35]	H. Couque, Philos. Trans. R. Soc. A 372, 20130218 (2014)
[36]	G. Dirras, H. Couque, L. Lilensten, A. Heczel, D. Tingaud, J.P. Couzinie, L. Perriere, J. Gubicza, I. Guillot, Mater. Charact. 111, 106 (2016)
[37]	S. Zhang, Z. Wang, H.J. Yang, J.W. Qiao, Z.H. Wang, Y.C. Wu, Intermetallics 121, 106699 (2020)
[38]	N. Kumar, Q. Ying, X. Nie, R.S. Mishra, Z. Tang, P.K. Liaw, R.E. Brennan, K.J. Doherty, K.C. Cho, Mater. Des. 86, 598 (2015)
[39]	B. Wang, A. Fu, X. Huang, B. Liu, Y. Liu, Z. Li, X. Zan, J. Mater. Eng. Perform. 25, 2985 (2016)
[40]	C.M. Cao, W. Tong, S.H. Bukhari, J. Xu, Y.X. Hao, P. Gu, H. Hao, L.M. Peng, Mater. Sci. Eng. A 759, 648 (2019)
[41]	X. Liu, Y. Wu, Y. Wang, J. Chen, R. Bai, L. Gao, Z. Xu, W.Y. Wang, C. Tan, X. Hui, J. Mater. Sci. Technol. 127, 164 (2022)
[42]	W.S. Lee, J.I. Cheng, C.F. Lin, Mater. Sci. Eng. A 381, 206 (2004)
[43]	J.Z. Lu, J.S. Zhong, K.Y. Luo, L. Zhang, H. Qi, M. Luo, X.J. Xu, J.Z. Zhou, Surf. Coat. Technol. 221, 88 (2013)
[44]	R.A. Al-Hammadi, R. Zhang, C. Cui, Z. Zhou, Y. Zhou, Acta Metall. Sin.-Engl. Lett. 37, 915 (2024)
[45]	M. Yang, X. Dong, Acta Metall. Sin.-Engl. Lett. 22, 40 (2009)
[46]	M.W. Vaughan, H. Lim, B. Pham, R. Seede, A.T. Polonsky, K.L. Johnson, P.J. Noell, Acta Mater. 274, 119977 (2024)
[47]	R.B. Sills, B.L. Boyce, Mater. Res. Lett. 8, 103 (2020) DOI
[48]	H. Wang, Q. He, X. Gao, Y. Shang, W. Zhu, W. Zhao, Z. Chen, H. Gong, Y. Yang, Adv. Mater. 36, 2305453 (2024)
[49]	Y. Cui, Y. Toku, Y. Kimura, Y. Ju, Y. Cui, Y. Toku, Y. Kimura, Y. Ju, Scr. Mater. 185, 12 (2020)
[50]	F. Liu, J. Mater. Sci. Technol. 155, 72 (2023)