Size-dependent deformation behavior of dual-phase, nanostructured CrCoNi medium-entropy alloy

More info
  • ReceivedMar 28, 2020
  • AcceptedApr 29, 2020
  • PublishedJul 29, 2020



the Australian Research Council Discovery Projects Grant

the Fundamental Research Funds for the Central Universities(SWU118105)

Australia Research Council(DE170100053)

and the Robinson Fellowship Scheme of the University of Sydney(G200726)


This work was supported by the Australian Research Council Discovery Projects Grant, and partly supported by the Fundamental Research Funds for the Central Universities (SWU118105). An X acknowledges the financial support from Australia Research Council (DE170100053) and the Robinson Fellowship Scheme of the University of Sydney (G200726). The authors acknowledge the facilities and the scientific and technical assistance of the Australian Microscopy and Microanalysis Research Facility (ammrf.org.au) node at the University of Adelaide: Adelaide Microscopy. In particular, the authors thank Dr Animesh Basak and Dr Ashley Slattery of Adelaide Microscopy for their support and expertise.

Interest statement

The authors declare that they have no conflict of interest.

Contributions statement

Chen Y, Xie Z, An X and Zhang S conceived the project. Chen Y conducted the FIB, microcompression and TEM experiments. Zhou Z fabricated the samples. Chen Y, An X, Liao X and Xie Z interpreted the results and wrote the manuscript. All authors contributed to the discussion of the results, and comments on the manuscript.

Author information

Yujie Chen obtained her BEng degree (first-class honors) in 2011 and PhD degree in materials science in 2016 from The University of Sydney. Upon completion of her PhD, she was employed as a postdoc in the School of Mechanical Engineering in the University of Adelaide in Australia. She is currently a research fellow in the Southwest University in China. Her current research involves microstructure optimization and mechanical properties enhancement of alloys, and calcified tissues.

Xianghai An received his PhD degree from the Institute of Metal Research, Chinese Academy of Sciences in 2012. After receiving his PhD degree, he commenced to work as a research fellow at The University of Sydney. He is currently a Lecture/Robinson Fellow at The University of Sydney. His research mainly focuses on materials design, mechanical behavior, and structure-property relationship of advanced metallic materials, nanomechanics and nanoplasticity, metallic additive manufacturing and advanced materials processing.

Sam Zhang received his PhD degree (1991) in ceramic materials at the University of Wisconsin-Madison, USA. He joined Nanyang Technological University as an associate professor and was promoted to full professor in 2006. He is currently a professor and head of the Center for Advanced Thin Films and Devices in the Southwest University in China. He is also Fellow of the Institute of Materials, Minerals and Mining, Fellow of the Royal Society of Chemistry and Fellow of the Thin Films Society. His research interests include preparation and characterization of hard yet tough ceramic nanocomposite coatings, and functional thin films.


[1] Yeh JW, Chen SK, Lin SJ, et al. Nanostructured high-entropy alloys with multiple principal elements: novel alloy design concepts and outcomes. Adv Eng Mater, 2004, 6299-303 CrossRef Google Scholar

[2] Cantor B, Chang ITH, Knight P, et al. Microstructural development in equiatomic multicomponent alloys. Mater Sci Eng-A, 2004, 375-377213-218 CrossRef Google Scholar

[3] Zhang Y, Zuo TT, Tang Z, et al. Microstructures and properties of high-entropy alloys. Prog Mater Sci, 2014, 611-93 CrossRef Google Scholar

[4] Zhang W, Liaw PK, Zhang Y. Science and technology in high-entropy alloys. Sci China Mater, 2018, 612-22 CrossRef Google Scholar

[5] Gludovatz B, Hohenwarter A, Catoor D, et al. A fracture-resistant high-entropy alloy for cryogenic applications. Science, 2014, 3451153-1158 CrossRef ADS Google Scholar

[6] Lin Q, An X, Liu H, et al. In-situ high-resolution transmission electron microscopy investigation of grain boundary dislocation activities in a nanocrystalline CrMnFeCoNi high-entropy alloy. J Alloys Compd, 2017, 709802-807 CrossRef Google Scholar

[7] Otto F, Yang Y, Bei H, et al. Relative effects of enthalpy and entropy on the phase stability of equiatomic high-entropy alloys. Acta Mater, 2013, 612628-2638 CrossRef Google Scholar

[8] Ma D, Grabowski B, Körmann F, et al. Ab initio thermodynamics of the CoCrFeMnNi high entropy alloy: Importance of entropy contributions beyond the configurational one. Acta Mater, 2015, 10090-97 CrossRef Google Scholar

[9] Yang X, Zhang Y. Prediction of high-entropy stabilized solid-solution in multi-component alloys. Mater Chem Phys, 2012, 132233-238 CrossRef Google Scholar

[10] Li Z, Pradeep KG, Deng Y, et al. Metastable high-entropy dual-phase alloys overcome the strength-ductility trade-off. Nature, 2016, 534227-230 CrossRef ADS Google Scholar

[11] Lu W, Liebscher CH, Dehm G, et al. Bidirectional transformation enables hierarchical nanolaminate dual-phase high-entropy alloys. Adv Mater, 2018, 301804727 CrossRef Google Scholar

[12] An XH, Wu SD, Wang ZG, et al. Significance of stacking fault energy in bulk nanostructured materials: insights from Cu and its binary alloys as model systems. Prog Mater Sci, 2019, 1011-45 CrossRef Google Scholar

[13] Liu J, Guo X, Lin Q, et al. Excellent ductility and serration feature of metastable CoCrFeNi high-entropy alloy at extremely low temperatures. Sci China Mater, 2019, 62853-863 CrossRef Google Scholar

[14] Gludovatz B, Hohenwarter A, Thurston KVS, et al. Exceptional damage-tolerance of a medium-entropy alloy CrCoNi at cryogenic temperatures. Nat Commun, 2016, 710602 CrossRef ADS arXiv Google Scholar

[15] Niu C, LaRosa CR, Miao J, et al. Magnetically-driven phase transformation strengthening in high entropy alloys. Nat Commun, 2018, 91363 CrossRef ADS Google Scholar

[16] Ma Y, Yuan F, Yang M, et al. Dynamic shear deformation of a CrCoNi medium-entropy alloy with heterogeneous grain structures. Acta Mater, 2018, 148407-418 CrossRef Google Scholar

[17] Miao J, Slone CE, Smith TM, et al. The evolution of the deformation substructure in a Ni-Co-Cr equiatomic solid solution alloy. Acta Mater, 2017, 13235-48 CrossRef Google Scholar

[18] Schuh B, Mendez-Martin F, Völker B, et al. Mechanical properties, microstructure and thermal stability of a nanocrystalline CoCrFeMnNi high-entropy alloy after severe plastic deformation. Acta Mater, 2015, 96258-268 CrossRef Google Scholar

[19] Slone CE, Miao J, George EP, et al. Achieving ultra-high strength and ductility in equiatomic CrCoNi with partially recrystallized microstructures. Acta Mater, 2019, 165496-507 CrossRef Google Scholar

[20] Sun SJ, Tian YZ, An XH, et al. Ultrahigh cryogenic strength and exceptional ductility in ultrafine-grained CoCrFeMnNi high-entropy alloy with fully recrystallized structure. Mater Today Nano, 2018, 446-53 CrossRef Google Scholar

[21] He JY, Wang H, Huang HL, et al. A precipitation-hardened high-entropy alloy with outstanding tensile properties. Acta Mater, 2016, 102187-196 CrossRef Google Scholar

[22] Guo L, Gu J, Gong X, et al. CALPHAD aided design of high entropy alloy to achieve high strength via precipitate strengthening. Sci China Mater, 2020, 63288-299 CrossRef Google Scholar

[23] Yang T, Zhao YL, Tong Y, et al. Multicomponent intermetallic nanoparticles and superb mechanical behaviors of complex alloys. Science, 2018, 362933-937 CrossRef ADS Google Scholar

[24] Seol JB, Bae JW, Li Z, et al. Boron doped ultrastrong and ductile high-entropy alloys. Acta Mater, 2018, 151366-376 CrossRef Google Scholar

[25] Li Z, Tasan CC, Springer H, et al. Interstitial atoms enable joint twinning and transformation induced plasticity in strong and ductile high-entropy alloys. Sci Rep, 2017, 740704 CrossRef ADS Google Scholar

[26] Song M, Zhou R, Gu J, et al. Nitrogen induced heterogeneous structures overcome strength-ductility trade-off in an additively manufactured high-entropy alloy. Appl Mater Today, 2020, 18100498 CrossRef Google Scholar

[27] Wang Z, Gu J, An D, et al. Characterization of the microstructure and deformation substructure evolution in a hierarchal high-entropy alloy by correlative EBSD and ECCI. Intermetallics, 2020, 121106788 CrossRef Google Scholar

[28] Lei Z, Liu X, Wu Y, et al. Enhanced strength and ductility in a high-entropy alloy via ordered oxygen complexes. Nature, 2018, 563546-550 CrossRef ADS Google Scholar

[29] Chen Y, Zhou Z, Munroe P, et al. Hierarchical nanostructure of CrCoNi film underlying its remarkable mechanical strength. Appl Phys Lett, 2018, 113081905 CrossRef ADS Google Scholar

[30] Tsianikas SJ, Chen Y, Xie Z. Deciphering deformation mechanisms of hierarchical dual-phase CrCoNi coatings. J Mater Sci Tech, 2020, 397-13 CrossRef Google Scholar

[31] Uchic MD, Dimiduk DM, Florando JN, et al. Sample dimensions influence strength and crystal plasticity. Science, 2004, 305986-989 CrossRef ADS Google Scholar

[32] Greer JR, Nix WD. Nanoscale gold pillars strengthened through dislocation starvation. Phys Rev B, 2006, 73245410 CrossRef ADS Google Scholar

[33] Shan ZW, Mishra RK, Syed Asif SA, et al. Mechanical annealing and source-limited deformation in submicrometre-diameter Ni crystals. Nat Mater, 2008, 7115-119 CrossRef ADS Google Scholar

[34] Wang ZJ, Li QJ, Shan ZW, et al. Sample size effects on the large strain bursts in submicron aluminum pillars. Appl Phys Lett, 2012, 100071906 CrossRef ADS Google Scholar

[35] Nix WD, Greer JR, Feng G, et al. Deformation at the nanometer and micrometer length scales: effects of strain gradients and dislocation starvation. Thin Solid Films, 2007, 5153152-3157 CrossRef ADS Google Scholar

[36] Hütsch J, Lilleodden ET. The influence of focused-ion beam preparation technique on microcompression investigations: Lathe vs. annular milling. Scripta Mater, 2014, 7749-51 CrossRef Google Scholar

[37] Guo W, Jägle E, Yao J, et al. Intrinsic and extrinsic size effects in the deformation of amorphous CuZr/nanocrystalline Cu nanolaminates. Acta Mater, 2014, 8094-106 CrossRef Google Scholar

[38] Chen CQ, Pei YT, De Hosson JTM. Effects of size on the mechanical response of metallic glasses investigated through in situ TEM bending and compression experiments. Acta Mater, 2010, 58189-200 CrossRef Google Scholar

[39] Giannuzzi LA, Stevie FA. A review of focused ion beam milling techniques for TEM specimen preparation. Micron, 1999, 30197-204 CrossRef Google Scholar

[40] Greer JR, De Hosson JTM. Plasticity in small-sized metallic systems: intrinsic versus extrinsic size effect. Prog Mater Sci, 2011, 56654-724 CrossRef Google Scholar

[41] Hull D, Bacon DJ. Introduction to Dislocations. Oxford: Elsevier, 2011. Google Scholar

[42] Liu SF, Wu Y, Wang HT, et al. Stacking fault energy of face-centered-cubic high entropy alloys. Intermetallics, 2018, 93269-273 CrossRef Google Scholar

[43] Lin Q, Liu J, An X, et al. Cryogenic-deformation-induced phase transformation in an FeCoCrNi high-entropy alloy. Mater Res Lett, 2018, 6236-243 CrossRef Google Scholar

[44] Schuh B, Völker B, Todt J, et al. Influence of annealing on microstructure and mechanical properties of a nanocrystalline CrCoNi medium-entropy alloy. Materials, 2018, 11662 CrossRef ADS Google Scholar

[45] Zhu ZG, Nguyen QB, Ng FL, et al. Hierarchical microstructure and strengthening mechanisms of a CoCrFeNiMn high entropy alloy additively manufactured by selective laser melting. Scripta Mater, 2018, 15420-24 CrossRef Google Scholar

[46] Lu L, Chen X, Huang X, et al. Revealing the maximum strength in nanotwinned copper. Science, 2009, 323607-610 CrossRef ADS Google Scholar

[47] Lu K, Lu L, Suresh S. Strengthening materials by engineering coherent internal boundaries at the nanoscale. Science, 2009, 324349-352 CrossRef ADS Google Scholar

[48] Chen B, Wang J, Gao Q, et al. Strengthening brittle semiconductor nanowires through stacking faults: insights from in situ mechanical testing. Nano Lett, 2013, 134369-4373 CrossRef ADS Google Scholar

[49] Chen Y, Burgess T, An X, et al. Effect of a high density of stacking faults on the Young’s modulus of GaAs nanowires. Nano Lett, 2016, 161911-1916 CrossRef ADS Google Scholar

[50] Li Z, Tasan CC, Pradeep KG, et al. A trip-assisted dual-phase high-entropy alloy: grain size and phase fraction effects on deformation behavior. Acta Mater, 2017, 131323-335 CrossRef Google Scholar

[51] Wang J, Sansoz F, Huang J, et al. Near-ideal theoretical strength in gold nanowires containing angstrom scale twins. Nat Commun, 2013, 41742 CrossRef ADS Google Scholar

[52] Wang L, Lu Y, Kong D, et al. Dynamic and atomic-scale understanding of the twin thickness effect on dislocation nucleation and propagation activities by in situ bending of Ni nanowires. Acta Mater, 2015, 90194-203 CrossRef Google Scholar

[53] Jang D, Greer JR. Size-induced weakening and grain boundary-assisted deformation in 60 nm grained Ni nanopillars. Scripta Mater, 2011, 6477-80 CrossRef Google Scholar

[54] Chen CQ, Pei YT, Kuzmin O, et al. Intrinsic size effects in the mechanical response of taper-free nanopillars of metallic glass. Phys Rev B, 2011, 83180201 CrossRef ADS Google Scholar

[55] Shan ZW, Li J, Cheng YQ, et al. Plastic flow and failure resistance of metallic glass: insight from in situ compression of nanopillars. Phys Rev B, 2008, 77155419 CrossRef ADS Google Scholar

[56] Kuzmin OV, Pei YT, Chen CQ, et al. Intrinsic and extrinsic size effects in the deformation of metallic glass nanopillars. Acta Mater, 2012, 60889-898 CrossRef Google Scholar

[57] Khalajhedayati A, Rupert TJ. Disruption of thermally-stable nanoscale grain structures by strain localization. Sci Rep, 2015, 510663 CrossRef ADS arXiv Google Scholar

[58] Rice JR. The localization of plastic deformation. In: Proceedings of the 14th International Congress of Theoretical and Applied Mechanics. Delft, 1976. 1–14. Google Scholar

[59] Volkert CA, Donohue A, Spaepen F. Effect of sample size on deformation in amorphous metals. J Appl Phys, 2008, 103083539 CrossRef ADS Google Scholar

[60] Jang D, Greer JR. Transition from a strong-yet-brittle to a stronger-and-ductile state by size reduction of metallic glasses. Nat Mater, 2010, 9215-219 CrossRef ADS Google Scholar

[61] Gao H, Ji B, Jager IL, et al. Materials become insensitive to flaws at nanoscale: lessons from nature. Proc Natl Acad Sci USA, 2003, 1005597-5600 CrossRef ADS Google Scholar

[62] Laplanche G, Gadaud P, Bärsch C, et al. Elastic moduli and thermal expansion coefficients of medium-entropy subsystems of the CrMnFeCoNi high-entropy alloy. J Alloys Compd, 2018, 746244-255 CrossRef Google Scholar

[63] Wu XL, Guo YZ, Wei Q, et al. Prevalence of shear banding in compression of Zr41Ti14Cu12.5Ni10Be22.5 pillars as small as 150 nm in diameter. Acta Mater, 2009, 573562-3571 CrossRef Google Scholar

[64] Schuster BE, Wei Q, Hufnagel TC, et al. Size-independent strength and deformation mode in compression of a Pd-based metallic glass. Acta Mater, 2008, 565091-5100 CrossRef Google Scholar

[65] Chen Y, An X, Liao X, et al. Effects of loading misalignment and tapering angle on the measured mechanical properties of nanowires. Nanotechnology, 2015, 26435704 CrossRef ADS Google Scholar

[66] Laplanche G, Kostka A, Reinhart C, et al. Reasons for the superior mechanical properties of medium-entropy CrCoNi compared to high-entropy CrMnFeCoNi. Acta Mater, 2017, 128292-303 CrossRef Google Scholar

[67] Zhang ZJ, Mao MM, Wang J, et al. Nanoscale origins of the damage tolerance of the high-entropy alloy CrMnFeCoNi. Nat Commun, 2015, 610143 CrossRef ADS arXiv Google Scholar

[68] Huang S, Huang H, Li W, et al. Twinning in metastable high-entropy alloys. Nat Commun, 2018, 92381 CrossRef ADS Google Scholar

[69] Zhang FX, Zhao S, Jin K, et al. Pressure-induced FCC to HCP phase transition in Ni-based high entropy solid solution alloys. Appl Phys Lett, 2017, 110011902 CrossRef ADS Google Scholar

[70] Zhao H, Song M, Ni S, et al. Atomic-scale understanding of stress-induced phase transformation in cold-rolled Hf. Acta Mater, 2017, 131271-279 CrossRef Google Scholar

[71] Armstrong RW, Coffey CS, Elban WL. Adiabatic heating at a dislocation pile-up avalanche. Acta Metall, 1982, 302111-2116 CrossRef Google Scholar

[72] Wei Q, Jia D, Ramesh KT, et al. Evolution and microstructure of shear bands in nanostructured Fe. Appl Phys Lett, 2002, 811240-1242 CrossRef ADS Google Scholar

[73] Zhang ZF, Eckert J, Schultz L. Difference in compressive and tensile fracture mechanisms of Zr59Cu20Al10Ni8Ti3 bulk metallic glass. Acta Mater, 2003, 511167-1179 CrossRef Google Scholar

[74] Zhang Z, Sheng H, Wang Z, et al. Dislocation mechanisms and 3D twin architectures generate exceptional strength-ductility-toughness combination in CrCoNi medium-entropy alloy. Nat Commun, 2017, 814390 CrossRef ADS Google Scholar

[75] Jang D, Li X, Gao H, et al. Deformation mechanisms in nanotwinned metal nanopillars. Nat Nanotech, 2012, 7594-601 CrossRef ADS Google Scholar

[76] Asaro RJ. Geometrical effects in the inhomogeneous deformation of ductile single crystals. Acta Metall, 1979, 27445-453 CrossRef Google Scholar

[77] Fujita H, Ueda S. Stacking faults and f.c.c. (γ) → h.c.p. (ε) transformation in 188-type stainless steel. Acta Metall, 1972, 20759-767 CrossRef Google Scholar

[78] Huang JY, Wu YK, Ye HQ. Allotropic transformation of cobalt induced by ball milling. Acta Mater, 1996, 441201-1209 CrossRef Google Scholar

[79] Liu Y, Yang H, Tan G, et al. Stress-induced FCC ↔ HCP martensitic transformation in CoNi. J Alloys Compd, 2004, 368157-163 CrossRef Google Scholar

  • Figure 1

    (a) A bright field TEM image of the as-deposited CrCoNi alloy showing the columnar structure containing a high density of planar defects; (b, c) STEM images of two separate grains showing the coexistence of HCP and FCC phases, as well as SFs and TBs.

  • Figure 2

    SEM images of undeformed and post-compressed pillars with diameters of (a, b) 1.45 µm, (d, e) 0.88 µm, (g, h) 0.23 µm; (c, f, i) engineering stress-strain curves corresponding to the pillars in (a, d, g), respectively.

  • Figure 3

    Yield stress versus pillar diameter for nanostructured CrCoNi alloy pillars.

  • Figure 4

    (a) A STEM image of the post-compressed pillar with a diameter of 1.45 µm failed catastrophically via shear banding. STEM images of the regions enclosed by (b) red rectangle, and (c) green rectangle in (a) showing the structure of shear bands. Magnified STEM images and the corresponding FFT (inset) of three selected regions: (d) near the shear band and (e) inside the shear band shown in (b), and (f) inside the shear band shown in (c).

  • Figure 5

    (a) An STEM image of the deformed pillar with a diameter of 0.88 µm in Fig. 2d, showing the two shear bands (SB1 and SB2). (b) A magnified STEM image of part of SB2. (c) An STEM image and its corresponding FFT (inset) exhibiting the FCC structure inside the shear band. (d, e) IFFT images of an L-C lock dislocation configurations inside the shear band. (f) An STEM image of the boundary between the sheared and un-sheared region indicating the misorientation and dislocations at the shear band boundary. (g) A shockley partial dislocation at FCC/HCP interfacial region. (h) An STEM image and its corresponding FFT (inset) demonstrating the highly deformed region beneath the top surface of the pillar that exhibits FCC-phased nanograins with the twin structure.

  • Figure 6

    Schematic illustration of the transition from catastrophic unsteady shear banding to stable and slow shear banding with decreasing pillar diameter. The minimum stress required for a shear band to fracture the pillar (blue solid line) crosses the experimental-measured flow stress (~4.2 GPa) when shear band initiates (green solid line) at a critical diameter, dc, where the transition between catastrophic and stable shear banding occurs. When the diameter is smaller than the critical size of ~0.93 µm, the strain energy raised by the flow stress is not high enough to allow for the shear band to fracture the pillar, thus, showing stable shear banding.

  • Figure 7

    The size effect on the deformation mode remains even if the tests were conducted on larger pillars with the same degree of tapering as the smaller ones. SEM images of undeformed and post-compressed pillars with the same tapering angle of 4.3°, but different diameters of (a, b) 1.25 µm, and (c, d) 0.4 µm.

  • Figure 8

    Schematic illustrations showing the structural evolution under shear banding in a nanostructured CrCoNi pillar.


Contact and support