Abstract
The microstructural evolution of a HfNbTaTiZr high-entropy alloy subjected to cold rolling and subsequent annealing was investigated. The dislocation activity dominates the deformation process. The microstuctural evolution of the alloy during cold rolling can be described as follows: (i) formation of dislocation tangles, (ii) formation of microbands, (iii) formation of thin laths and microshear bands containing thin laths, (iv) the transverse breakdown of the lath to elongated segment, and (v) formation of fine grains. During annealing at 800 and 1000 °C, decomposition of the metastable high-temperature body-centered cubic phase proceeded through a phase separation reaction. Annealing at 800 °C resulted in a nonrecrystallized microstructure with abundant second-phase particles distributed randomly. The second-phase particles with an average size of ∼145 nm were enriched in Ta and Nb, while the chemical composition of the matrix was close to the average composition of the alloy. Meanwhile, an unknown phase slightly enriched in Hf, Zr, and Ti was detected in the interfacial region between the second-phase particles.
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J.W. Yeh, S.K. Chen, S.J. Lin, J.Y. Gan, T.S. Chin, T.T. Shun, C.H. Tsau, and S.Y. Chang: Nanostructured high-entropy alloys with multiple principal elements: Novel alloy design concepts and outcomes. Adv. Eng. Mater. 6 (5), 299 (2004).
B. Cantor, I. Chang, P. Knight, and A. Vincent: Microstructural development in equiatomic multicomponent alloys. Mater. Sci. Eng., A 375, 213 (2004).
Y.F. Ye, Q. Wang, J. Lu, C.T. Liu, and Y. Yang: High-entropy alloy: Challenges and prospects. Mater. Today 19 (6), 349 (2016).
Y.D. Wu, Y.H. Cai, T. Wang, J.J. Si, J. Zhu, Y.D. Wang, and X.D. Hui: A refractory Hf25Nb25Ti25Zr25 high-entropy alloy with excellent structural stability and tensile properties. Mater. Lett. 130, 277 (2014).
B. Gludovatz, A. Hohenwarter, D. Catoor, E.H. Chang, E.P. George, and R.O. Ritchie: A fracture-resistant high-entropy alloy for cryogenic applications. Science 345 (6201), 1153 (2014).
Z. Wu, H. Bei, G.M. Pharr, and E.P. George: Temperature dependence of the mechanical properties of equiatomic solid solution alloys with face-centered cubic crystal structures. Acta Mater. 81, 428 (2014).
M.H. Chuang, M.H. Tsai, W.R. Wang, S.J. Lin, and J.W. Yeh: Microstructure and wear behavior of AlxCo1.5CrFeNi1.5Tiy high-entropy alloys. Acta Mater. 59 (16), 6308 (2011).
Z. Tang, L. Huang, W. He, and P. Liaw: Alloying and processing effects on the aqueous corrosion behavior of high-entropy alloys. Entropy 16 (2), 895 (2014).
Y.L. Chou, Y.C. Wang, J.W. Yeh, and H.C. Shih: Pitting corrosion of the high-entropy alloy Co1.5CrFeNi1.5Ti0.5Mo0.1 in chloride-containing sulphate solutions. Corros. Sci. 52 (10), 3481 (2010).
C.M. Liu, H.M. Wang, S.Q. Zhang, H.B. Tang, and A.L. Zhang: Microstructure and oxidation behavior of new refractory high entropy alloys. J. Alloys Compd. 583, 162 (2014).
M. Feuerbacher, M. Heidelmann, and C. Thomas: Hexagonal high-entropy alloys. Mater. Res. Lett. 3 (1), 1 (2014).
K.M. Youssef, A.J. Zaddach, C. Niu, D.L. Irving, and C.C. Koch: A novel low-density, high-hardness, high-entropy alloy with close-packed single-phase nanocrystalline structures. Mater. Res. Lett. 3 (2), 95 (2014).
J.W. Yeh: Recent progress in high-entropy alloys. Ann. Chim.-Sci. Mat. 31 (6), 633 (2006).
M.H. Tsai and J.W. Yeh: High-entropy alloys: A critical review. Mater. Res. Lett. 2 (3), 107 (2014).
M.C. Gao, J.W. Yeh, P.K. Liaw, and Y. Zhang: High-Entropy Alloys: Fundamentals and Applications (Springer, Cham, 2015).
M.C. Gao, B. Zhang, S.M. Guo, J.W. Qiao, and J.A. Hawk: High-entropy alloys in hexagonal close-packed structure. Metall. Mater. Trans. A 47 (7), 3322 (2016).
W.H. Liu, Y. Wu, J.Y. He, T.G. Nieh, and Z.P. Lu: Grain growth and the Hall–Petch relationship in a high-entropy FeCrNiCoMn alloy. Scr. Mater. 68 (7), 526 (2013).
M.J. Yao, K.G. Pradeep, C.C. Tasan, and D. Raabe: A novel, single phase, non-equiatomic FeMnNiCoCr high-entropy alloy with exceptional phase stability and tensile ductility. Scr. Mater. 72–73, 5 (2014).
Y. Zou, S. Maiti, W. Steurer, and R. Spolenak: Size-dependent plasticity in an Nb25Mo25Ta25W25 refractory high-entropy alloy. Acta Mater. 65, 85 (2014).
Y. Zhang, T.T. Zuo, Z. Tang, M.C. Gao, K.A. Dahmen, P.K. Liaw, and Z.P. Lu: Microstructures and properties of high-entropy alloys. Prog. Mater. Sci. 61, 1 (2014).
N. Stepanov, M. Tikhonovsky, N. Yurchenko, D. Zyabkin, M. Klimova, S. Zherebtsov, A. Efimov, and G. Salishchev: Effect of cryo-deformation on structure and properties of CoCrFeNiMn high-entropy alloy. Intermetallics 59, 8 (2015).
O.N. Senkov, J.M. Scott, S.V. Senkova, D.B. Miracle, and C.F. Woodward: Microstructure and room temperature properties of a high-entropy TaNbHfZrTi alloy. J. Alloys Compd. 509 (20), 6043 (2011).
O.N. Senkov, J.M. Scott, S.V. Senkova, F. Meisenkothen, D.B. Miracle, and C.F. Woodward: Microstructure and elevated temperature properties of a refractory TaNbHfZrTi alloy. J. Mater. Sci. 47 (9), 4062 (2012).
O.N. Senkov and S.L. Semiatin: Microstructure and properties of a refractory high-entropy alloy after cold working. J. Alloys Compd. 649, 1110 (2015).
S.J. Pennycook and P.D. Nellist: Scanning Transmission Electron Microscopy: Imaging and Analysis (Springer, New York, 2011).
Z.J. Li, A. Godfrey, and Q. Liu: Evolution of microstructure and local crystallographic orientations in rolled Al–1% Mn single crystals of {001}〈110〉 orientation. Acta Mater. 52 (1), 149 (2004).
J. Wert, Q. Liu, and N. Hansen: Dislocation boundary formation in a cold-rolled cube-oriented Al single crystal. Acta Mater. 45 (6), 2565 (1997).
D.K. Yang, P. Cizek, P.D. Hodgson, and C.E. Wen: Microstructure evolution and nanograin formation during shear localization in cold-rolled titanium. Acta Mater. 58 (13), 4536 (2010).
S. Guo, C. Ng, J. Lu, and C.T. Liu: Effect of valence electron concentration on stability of fcc or bcc phase in high entropy alloys. J. Appl. Phys. 109 (10), 103505 (2011).
Y. Zhang, Y.J. Zhou, J.P. Lin, G.L. Chen, and P.K. Liaw: Solid-solution phase formation rules for multi-component alloys. Adv. Eng. Mater. 10 (6), 534 (2008).
S. Guo and C.T. Liu: Phase stability in high entropy alloys: formation of solid-solution phase or amorphous phase. Prog. Nat. Sci.: Mater. Int. 21 (6), 433 (2011).
D. Hughes: Microstructural evolution in a non-cell forming metal: Al–Mg. Acta Metall. Mater. 41 (5), 1421 (1993).
D. Hughes and N. Hansen: Microstructural evolution in nickel during rolling and torsion. Mater. Sci. Technol. 7 (6), 544 (1991).
D. Hughes, N. Hansen, and D. Bammann: Geometrically necessary boundaries, incidental dislocation boundaries and geometrically necessary dislocations. Scr. Mater. 48 (2), 147 (2003).
D. Kuhlmann-Wilsdorf and N. Hansen: Geometrically necessary, incidental and subgrain boundaries. Scr. Metall. Mater. 25 (7), 1557 (1991).
B.L. Li, A. Godfrey, Q.C. Meng, Q. Liu, and N. Hansen: Microstructural evolution of IF-steel during cold rolling. Acta Mater. 52 (4), 1069 (2004).
Q. Xue, E.K. Cerreta, and G.T.I. Gray: Microstructural characteristics of post-shear localization in cold-rolled 316L stainless steel. Acta Mater. 55 (2), 691 (2007).
K.Y. Zhu, A. Vassel, F. Brisset, K. Lu, and J. Lu: Nanostructure formation mechanism of alpha-titanium using SMAT. Acta Mater. 52 (14), 4101 (2004).
Q. Xue and G.T.I. Gray: Development of adiabatic shear bands in annealed 316L stainless steel: Part II. TEM studies of the evolution of microstructure during deformation localization. Metall. Mater. Trans. A 37 (8), 2447 (2006).
C.R. Afonso, P.L. Ferrandini, A.J. Ramirez, and R. Caram: High resolution transmission electron microscopy study of the hardening mechanism through phase separation in a β-Ti–35Nb–7Zr–5Ta alloy for implant applications. Acta Biomater. 6 (4), 1625 (2010).
O. Senkov, S. Senkova, and C. Woodward: Effect of aluminum on the microstructure and properties of two refractory high-entropy alloys. Acta Mater. 68, 214 (2014).
ACKNOWLEDGMENTS
The financial supports from Fundamental Research Funds for the Central Universities of Central South University, Hunan Provincial National Natural Science Foundation of China (2015JJ2206), and Project of Innovation-driven Plan in Central South University (2015CXS003) are appreciated.
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Wu, W., Ni, S., Liu, Y. et al. Effects of cold rolling and subsequent annealing on the microstructure of a HfNbTaTiZr high-entropy alloy. Journal of Materials Research 31, 3815–3823 (2016). https://doi.org/10.1557/jmr.2016.445
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DOI: https://doi.org/10.1557/jmr.2016.445