Formation of strong and ductile FeNiCoCrB network-structured high-entropy alloys by fluxing

Abstract

A series of [(FeNiCo)_0.85Cr_0.15]_100-xB_x (x = 12, 15, 17) high-entropy alloys with network-like microstructures (N-HEAs) and a wavelength of 3-5 μm was prepared using the fluxing method. The novel N-HEAs exhibited higher strength and ductility compared with samples obtained by suction casting. Neutron diffraction and scanning electron microscopy measurements showed that the network-like structure contained soft face-centered cubic (FCC) and hard tetragonal Cr₂B-type sub-networks. The network-like structure was formed during the solidification of the molten alloy from a deeply undercooled state, achieved by removing impurities and most metallic oxides through B₂O₃ fluxing. The mechanical properties could be tuned by modifying the composition to change the volume fractions of the different sub-networks. When x decreased from 17 to 12, the compressive yield strength decreased from 1.6 to 1.1 GPa, while the compressive strain increased from ~20% to ~70%. The N-HEA samples with x = 12 and 15 also exhibited a good tensile ductility of 19% and 14%, respectively. In situ synchrotron X-ray diffraction results revealed an inhomogeneous deformation behavior, i.e., the soft FCC phase yielded prior to the hard Cr₂B-type phase, which bore more stress in the initial stage of the plastic deformation. In the later stage of the plastic deformation, the ductility of the sample was provided by the FCC phase, together with some contributions from the Cr₂B-type phase.

Keywords

Network-structured high-entropy alloys / neutron and X-ray diffraction / mechanical properties / fluxing method

References

[1] Zhang Y,Tang Z.Microstructures and properties of high-entropy alloys.Prog Mater Sci2014;61:1-93

[2] Yeh J,Lin S.Nanostructured high-entropy alloys with multiple principal elements: novel alloy design concepts and outcomes.Adv Eng Mater2004;6:299-303

[3] Cantor B,Knight P.Microstructural development in equiatomic multicomponent alloys.Mater Sci Eng A2004;375-377:213-8

[4] Ye Y,Lu J,Yang Y.High-entropy alloy: challenges and prospects.Mater Today2016;19:349-62

[5] George EP,Ritchie RO.High-entropy alloys.Nat Rev Mater2019;4:515-34

[6] Naeem M,Zhang F.Cooperative deformation in high-entropy alloys at ultralow temperatures.Sci Adv2020;6:eaax4002 PMCID:PMC7101227

[7] Liu D,Kabra S.Exceptional fracture toughness of CrCoNi-based medium- and high-entropy alloys at 20 kelvin.Science2022;378:978-83

[8] Gludovatz B,Catoor D,George EP.A fracture-resistant high-entropy alloy for cryogenic applications.Science2014;345:1153-8

[9] Zhang C,Tang YT.Strong and ductile FeNiCoAl-based high-entropy alloys for cryogenic to elevated temperature multifunctional applications.Acta Mater2023;242:118449

[10] Han L,Souza Filho IR.A mechanically strong and ductile soft magnet with extremely low coercivity.Nature2022;608:310-6 PMCID:PMC9365696

[11] Yang T,Tong Y.Multicomponent intermetallic nanoparticles and superb mechanical behaviors of complex alloys.Science2018;362:933-7

[12] Ding Q,Chen X.Tuning element distribution, structure and properties by composition in high-entropy alloys.Nature2019;574:223-7

[13] Yang T,Li WP.Ultrahigh-strength and ductile superlattice alloys with nanoscale disordered interfaces.Science2020;369:427-32

[14] Zhang BB,Mei QS,Lu K.Inhibiting creep in nanograined alloys with stable grain boundary networks.Science2022;378:659-63

[15] Wang J,Fu S.Ultrahard BCC-AlCoCrFeNi bulk nanocrystalline high-entropy alloy formed by nanoscale diffusion-induced phase transition.J Mater Sci Technol2022;115:29-39

[16] Han L,Wang L,Zhou R.A eutectic high-entropy alloy with good high-temperature strength-plasticity balance.Mater Res Lett2019;7:460-6

[17] Han L,Li Z,Liu CT.A novel equiaxed eutectic high-entropy alloy with excellent mechanical properties at elevated temperatures.Mater Res Lett2020;8:373-82

[18] Li Z.Influence of compositional inhomogeneity on mechanical behavior of an interstitial dual-phase high-entropy alloy.Mater Chem Phys2018;210:29-36

[19] Bhattacharjee P,Zaid M.Microstructure and texture evolution during annealing of equiatomic CoCrFeMnNi high-entropy alloy.J Alloys Compd2014;587:544-52

[20] Zhang K,Zhang J.Annealing on the structure and properties evolution of the CoCrFeNiCuAl high-entropy alloy.J Alloys Compd2010;502:295-9

[21] Kui HW,Turnbull D.Formation of bulk metallic glass by fluxing.Appl Phys Lett1984;45:615-6

[22] Utigard TA.The properties and uses of fluxes in molten aluminum processing.JOM1998;50:38-43

[23] Lau C.Microstructures of undercooled germanium.Acta Metall Mater1991;39:323-7

[24] Ho C,Yip Y,Kui H.Ductile Fe₈₃C₁₇ alloys of ultrafine networklike microstructure.Metall Mat Trans A2010;41:3443-51

[25] Ho CM.Ductile and high strength white cast iron of ultrafine interconnected network morphology.Metall Mat Trans A2011;42:3826-37

[26] Lu Y,Guo S.A promising new class of high-temperature alloys: eutectic high-entropy alloys.Sci Rep2014;4:6200

[27] Gao X,Zhang B.Microstructural origins of high strength and high ductility in an AlCoCrFeNi_2.1 eutectic high-entropy alloy.Acta Mater2017;141:59-66

[28] Wu Z,Wu Z.Spinodal decomposition in Pd_41.25Ni_41.25P_17.5 bulk metallic glasses.J Non Cryst Solids2014;385:40-6

[29] Chen J,Lu H,Wang F.The general purpose powder diffractometer at CSNS.Phys Rev B Condens Matter2018;551:370-2

[30] Allen C. Larson RBVD. General structure analysis system (GSAS) report LAUR 86-748. Los Alamos national laboratory. 2004. Available from: https://11bm.xray.aps.anl.gov/documents/GSASManual.pdf [Last accessed on 22 March 2023]

[31] Lan S,Kelton KF,Fan J.Structural crossover in a supercooled metallic liquid and the link to a liquid-to-liquid phase transition.Appl Phys Lett2016;108:211907

[32] Wu X,Rehm C.Ultra-small-angle neutron scattering study on temperature-dependent precipitate evolution in CoCrFeNiMo_0.3 high entropy alloy.Acta Mater2022;222:117446

[33] Xu S,Cui Y.Mechanical properties and deformation mechanisms of a novel austenite-martensite dual phase steel.Int J Plast2020;128:102677

[34] Clausen B,Bourke MA.Lattice strain evolution during uniaxial tensile loading of stainless steel.Mater Sci Eng A1999;259:17-24

[35] Pang J,Wright J.The generation of intergranular strains in 309H stainless steel under uniaxial loading.Acta Mater2000;48:1131-40

[36] Ma L,Nie Z.Reversible deformation-induced martensitic transformation in Al_0.6CoCrFeNi high-entropy alloy investigated by in situ synchrotron-based high-energy X-ray diffraction.Acta Mater2017;128:12-21

[37] Fu B,Wang Y,Sun Z.Micromechanical behavior of TRIP-assisted multiphase steels studied with in situ high-energy X-ray diffraction.Acta Mater2014;76:342-54

[38] Warren BE. X-ray diffraction. Courier Corporation; 1990. Available from: https://scholar.google.com/scholar?cluster=15231993657912304740&hl=zh-TW&as_sdt=0,5 [Last accessed on 22 March 2023]

[39] He H,Zhang F.Stacking fault driven phase transformation in CrCoNi medium entropy alloy.Nano Lett2021;21:1419-26

[40] Taylor GI. Plastic strain in metals. Available from: https://cir.nii.ac.jp/crid/1573105974372618880 [Last accessed on 22 March 2023]

[41] Cheng S,Wang XL.Deformation crossover: from nano- to mesoscale.Phys Rev Lett2009;103:035502

[42] Wang B,Naeem M.Deformation of CoCrFeNi high entropy alloy at large strain.Scr Mater2018;155:54-7

[43] Chen X,Cheng Z.Direct observation of chemical short-range order in a medium-entropy alloy.Nature2021;592:712-6

[44] Lan S,Wu Z.A medium-range structure motif linking amorphous and crystalline states.Nat Mater2021;20:1347-52

[45] Lan S,Wei X.Structure origin of a transition of classic-to-avalanche nucleation in Zr-Cu-Al bulk metallic glasses.Acta Mater2018;149:108-18

[46] Li Q.Formation of bulk magnetic nanostructured Fe₄₀Ni₄₀P₁₄B₆ alloys by metastable liquid state phase separation..MRS Online Proc Lib1999;581:277-82

[47] Cahn JW.On spinodal decomposition.Acta Metall1961;9:795-801

[48] Nagashio K.Growth mechanism of twin-related and twin-free facet Si dendrites.Acta Mater2005;53:3021-9.

[49] Schwarz M,Eckler K.Physical mechanism of grain refinement in solidification of undercooled melts.Phys Rev Lett1994;73:1380-3

[50] Herlach DM,Pichon PY.Crystal growth kinetics in undercooled melts of pure Ge, Si and Ge-Si alloys.Philos Trans A Math Phys Eng Sci2018;376:20170205 PMCID:PMC5784096

[51] Jackson K.The present state of the theory of crystal growth from the melt.J Cryst Growth1974;24-25:130-6

[52] Cahn JW.Theory of crystal growth and interface motion in crystalline materials.Acta Metall1960;8:554-62

[53] Fan J,Yu P.A novel high-entropy alloy with a dendrite-composite microstructure and remarkable compression performance.Scr Mater2019;159:18-23

[54] Shi P,Zheng T.Enhanced strength-ductility synergy in ultrafine-grained eutectic high-entropy alloys by inheriting microstructural lamellae.Nat Commun2019;10:489 PMCID:PMC6353877

[55] Wu Z,Otto F,George E.Recovery, recrystallization, grain growth and phase stability of a family of FCC-structured multi-component equiatomic solid solution alloys.Intermetallics2014;46:131-40

[56] Senkov O,Scott J.Mechanical properties of Nb₂₅Mo₂₅Ta₂₅W₂₅ and V₂₀Nb₂₀Mo₂₀Ta₂₀W₂₀ refractory high entropy alloys.Intermetallics2011;19:698-706

[57] Wang Z,Guo W.The effect of carbon on the microstructures, mechanical properties, and deformation mechanisms of thermo-mechanically treated Fe_40.4Ni_11.3Mn_34.8Al_7.5Cr₆ high entropy alloys.Acta Mater2017;126:346-60

[58] Takeuchi A.Classification of bulk metallic glasses by atomic size difference.Mater Trans2005;46:2817-29

[59] Harjo S,Lukáš P.In situ neutron diffraction study of α-γ Fe-Cr-Ni alloys under tensile deformation.Acta Mater2001;49:2471-9

[60] Lee S,De Cooman BC.Analysis of the plasticity-enhancing mechanisms in 12 pctMn Austeno-ferritic steel by in situ neutron diffraction.Metall Mat Trans A2014;45:5823-8

[61] Tomota Y,Adachi Y.Tensile behavior of TRIP-aided multi-phase steels studied by in situ neutron diffraction.Acta Mater2004;52:5737-45

[62] Naeem M,Harjo S.Temperature-dependent hardening contributions in CrFeCoNi high-entropy alloy.Acta Mater2021;221:117371

[63] Das A.Geometry of dimples and its correlation with mechanical properties in austenitic stainless steel.Scr Mater2008;59:1014-7

[64] Parrington RJ.Fractography of metals and plastics.Pract Fail Anal2002;2:16-9