High-content ductile coherent nanoprecipitates achieve ultrastrong high-entropy alloys

Precipitation-hardening high-entropy alloys (PH-HEAs) with good strength−ductility balances are a promising candidate for advanced structural applications. However, current HEAs emphasize near-equiatomic initial compositions, which limit the increase of intermetallic precipitates that are closely related to the alloy strength. Here we present a strategy to design ultrastrong HEAs with high-content nanoprecipitates by phase separation, which can generate a near-equiatomic matrix in situ while forming strengthening phases, producing a PH-HEA regardless of the initial atomic ratio. Accordingly, we develop a non-equiatomic alloy that utilizes spinodal decomposition to create a low-misfit coherent nanostructure combining a near-equiatomic disordered face-centered-cubic (FCC) matrix with high-content ductile Ni3Al-type ordered nanoprecipitates. We find that this spinodal order–disorder nanostructure contributes to a strength increase of ~1.5 GPa (>560%) relative to the HEA without precipitation, achieving one of the highest tensile strength (1.9 GPa) among all bulk HEAs reported previously while retaining good ductility (>9%).High entropy alloys usually emphasize equiatomic compositions, which restrict the compositions available to induce strengthening via precipitation. Here the authors use spinodal decomposition in a five-element alloy to obtain high content nanophases and the highest tensile strength reported to date.

[1]  Dierk Raabe,et al.  A novel, single phase, non-equiatomic FeMnNiCoCr high-entropy alloy with exceptional phase stability and tensile ductility , 2014 .

[2]  I. Guillot,et al.  Elastic and plastic properties of as-cast equimolar TiHfZrTaNb high-entropy alloy , 2016 .

[3]  D. Seidman,et al.  Effects of solute concentrations on kinetic pathways in Ni–Al–Cr alloys , 2007, 0706.3916.

[4]  J. B. Zhu,et al.  Microstructure and the properties of FeCoCuNiSnx high entropy alloys , 2012 .

[5]  E. George,et al.  Tensile properties of high- and medium-entropy alloys , 2013 .

[6]  Nikita Stepanov,et al.  Tensile properties of an AlCrCuNiFeCo high-entropy alloy in as-cast and wrought conditions , 2012 .

[7]  N. Jones,et al.  High-entropy alloys: a critical assessment of their founding principles and future prospects , 2016 .

[8]  P. Liaw,et al.  Processing effects on the magnetic and mechanical properties of FeCoNiAl0.2Si0.2 high entropy alloy , 2013, International Journal of Minerals, Metallurgy, and Materials.

[9]  I. Baker,et al.  Effects of annealing and thermo-mechanical treatment on the microstructures and mechanical properties of a carbon-doped FeNiMnAl multi-component alloy , 2017 .

[10]  Xiaoxu Huang,et al.  Revealing the Maximum Strength in Nanotwinned Copper , 2009, Science.

[11]  Yong Zhang,et al.  The Al Effects of Co-Free and V-Containing High-Entropy Alloys , 2017 .

[12]  Sheng Guo,et al.  Ultrafine-Grained AlCoCrFeNi2.1 Eutectic High-Entropy Alloy , 2016 .

[13]  R. Ritchie,et al.  A fracture-resistant high-entropy alloy for cryogenic applications , 2014, Science.

[14]  H. Bei,et al.  Microstructures and mechanical properties of compositionally complex Co-free FeNiMnCr18 FCC solid solution alloy , 2015 .

[15]  J. Yeh,et al.  Microstructure characterization of AlxCoCrCuFeNi high-entropy alloy system with multiprincipal elements , 2005 .

[16]  G. Pharr,et al.  Temperature dependence of the mechanical properties of equiatomic solid solution alloys with face-centered cubic crystal structures , 2014 .

[17]  Dierk Raabe,et al.  Decomposition of the single-phase high-entropy alloy CrMnFeCoNi after prolonged anneals at intermediate temperatures , 2016 .

[18]  D. Miracle,et al.  A critical review of high entropy alloys and related concepts , 2016 .

[19]  Zhou Wang,et al.  Effect of coherent L12 nanoprecipitates on the tensile behavior of a fcc-based high-entropy alloy , 2017 .

[20]  B. S. Murty,et al.  Decomposition in multi-component AlCoCrCuFeNi high-entropy alloy , 2011 .

[21]  Oleg N. Senkov,et al.  Microstructure and properties of a refractory high-entropy alloy after cold working , 2015 .

[22]  Yuan-Sheng Huang,et al.  On the elemental effect of AlCoCrCuFeNi high-entropy alloy system , 2007 .

[23]  Dierk Raabe,et al.  Ultrastrong steel via minimal lattice misfit and high-density nanoprecipitation , 2017, Nature.

[24]  H. Fraser,et al.  Precipitation of ordered phases in metallic solid solutions: A synergistic clustering and ordering process , 2011 .

[25]  Jinshan Li,et al.  Effect of aging temperature on microstructure and properties of AlCoCrCuFeNi high-entropy alloy , 2009 .

[26]  Peter Hodgson,et al.  Tension/compression asymmetry in additive manufactured face centered cubic high entropy alloy , 2017 .

[27]  Zhihua Wang,et al.  Superior high tensile elongation of a single-crystal CoCrFeNiAl0.3 high-entropy alloy by Bridgman solidification , 2014 .

[28]  U. Glatzel,et al.  Phase separation in equiatomic AlCoCrFeNi high-entropy alloy. , 2013, Ultramicroscopy.

[29]  Huajian Gao,et al.  Dislocation nucleation governed softening and maximum strength in nano-twinned metals , 2010, Nature.

[30]  Tongmin Wang,et al.  A multi-component AlCrFe2Ni2 alloy with excellent mechanical properties , 2016 .

[31]  C. Liu,et al.  Precipitation hardening in CoCrFeNi-based high entropy alloys , 2017 .

[32]  Jun Wang,et al.  Strengthening of nanoprecipitations in an annealed Al0.5CoCrFeNi high entropy alloy , 2016 .

[33]  J. Yeh,et al.  Mechanical performance of the AlxCoCrCuFeNi high-entropy alloy system with multiprincipal elements , 2005 .

[34]  Bin Liu,et al.  Ductile CoCrFeNiMox high entropy alloys strengthened by hard intermetallic phases , 2016 .

[35]  P. Liaw,et al.  Deviation from high-entropy configurations in the atomic distributions of a multi-principal-element alloy , 2015, Nature Communications.

[36]  Ji-Jung Kai,et al.  Heterogeneous precipitation behavior and stacking-fault-mediated deformation in a CoCrNi-based medium-entropy alloy , 2017 .

[37]  J. Lenkkeri,et al.  An investigation of elastic moduli of vanadium-chromium alloys , 1978 .

[38]  J. Banhart,et al.  Effect of decomposition of the Cr-Fe-Co rich phase of AlCoCrCuFeNi high entropy alloy on magnetic properties. , 2011, Ultramicroscopy.

[39]  I. Guillot,et al.  Design and tensile properties of a bcc Ti-rich high-entropy alloy with transformation-induced plasticity , 2017 .

[40]  Huijun Kang,et al.  A Promising New Class of High-Temperature Alloys: Eutectic High-Entropy Alloys , 2014, Scientific Reports.

[41]  A. Ardell,et al.  Precipitation hardening , 1985 .

[42]  Q. Jiang,et al.  Microstructure and tensile properties of FeMnNiCuCoSnx high entropy alloys , 2013 .

[43]  Tongmin Wang,et al.  Effect of electromagnetic stirring on microstructure and properties of Al0.5CoCrCuFeNi alloy , 2012 .

[44]  N. Tsuji,et al.  Tailoring nanostructures and mechanical properties of AlCoCrFeNi2.1 eutectic high entropy alloy using thermo-mechanical processing , 2016 .

[45]  K. Dahmen,et al.  Microstructures and properties of high-entropy alloys , 2014 .

[46]  G. Eggeler,et al.  The influences of temperature and microstructure on the tensile properties of a CoCrFeMnNi high-entropy alloy , 2013 .

[47]  C. Tasan,et al.  A TRIP-assisted dual-phase high-entropy alloy: Grain size and phase fraction effects on deformation behavior , 2017 .

[48]  D. Riley,et al.  An experimental investigation of extrapolation methods in the derivation of accurate unit-cell dimensions of crystals , 1945 .

[49]  R. Mishraa,et al.  Effect of Microstructure on the Deformation Mechanism of Friction Stir-Processed Al 0 . 1 CoCrFeNi High Entropy Alloy , 2014 .

[50]  A. L. Patterson.  The Scherrer Formula for X-Ray Particle Size Determination , 1939 .

[51]  Yang Ren,et al.  Optimizing the coupled effects of Hall-Petch and precipitation strengthening in a Al0.3CoCrFeNi high entropy alloy , 2017 .

[52]  Sheng Guo,et al.  Directly cast bulk eutectic and near-eutectic high entropy alloys with balanced strength and ductility in a wide temperature range , 2017 .

[53]  C. Persson,et al.  Alloy design for intrinsically ductile refractory high-entropy alloys , 2016 .

[54]  J. Yeh,et al.  Effects of Al addition on the microstructure and mechanical property of AlxCoCrFeNi high-entropy alloys , 2012 .

[55]  John W. Cahn,et al.  Phase Separation by Spinodal Decomposition in Isotropic Systems , 1965 .

[56]  C. Tasan,et al.  Metastable high-entropy dual-phase alloys overcome the strength–ductility trade-off , 2016, Nature.

[57]  P. Munroe,et al.  A new high-strength spinodal alloy , 2005 .

[58]  P. Liaw,et al.  Microstructures and mechanical properties of AlxCrFeNiTi0.25 alloys , 2015 .

[59]  T. Shun,et al.  Nanostructured High‐Entropy Alloys with Multiple Principal Elements: Novel Alloy Design Concepts and Outcomes , 2004 .

[60]  Peter K. Liaw,et al.  Mechanical properties of the high-entropy alloy Ag0.5CoCrCuFeNi at temperatures of 4.2–300 K , 2013 .

[61]  C. Liu,et al.  Ductile Ordered Intermetallic Alloys , 1984, Science.

[62]  N. Stepanov,et al.  Effect of cryo-deformation on structure and properties of CoCrFeNiMn high-entropy alloy , 2015 .

[63]  R. Scattergood,et al.  Tensile properties of low-stacking fault energy high-entropy alloys , 2015 .

[64]  K. Lu,et al.  Strengthening Materials by Engineering Coherent Internal Boundaries at the Nanoscale , 2009, Science.

[65]  C. Liu,et al.  Effects of Nb additions on the microstructure and mechanical property of CoCrFeNi high-entropy alloys , 2015 .

[66]  Y. Ivanisenko,et al.  Novel Fe36Mn21Cr18Ni15Al10 high entropy alloy with bcc/B2 dual-phase structure , 2017 .

[67]  Chuang Dong,et al.  A cuboidal B2 nanoprecipitation-enhanced body-centered-cubic alloy Al 0.7 CoCrFe 2 Ni with prominent tensile properties , 2016 .

[68]  John J. Lewandowski,et al.  High-entropy Al 0.3 CoCrFeNi alloy fibers with high tensile strength and ductility at ambient and cryogenic temperatures , 2017 .

[69]  Yong Zhang,et al.  Evolution of Microstructures and Properties of the AlxCrCuFeNi2 High-Entropy Alloys , 2013 .

[70]  Seiichi Watanabe,et al.  CoCrFeNiTi-based high-entropy alloy with superior tensile strength and corrosion resistance achieved by a combination of additive manufacturing using selective electron beam melting and solution treatment , 2017 .

[71]  E. J. Pickering,et al.  Research data supporting "Fine-scale precipitation in the high-entropy alloy Al0.5CrFeCoNiCu" , 2015 .

[72]  Kaisheng Ming,et al.  Precipitation strengthening of ductile Cr15Fe20Co35Ni20Mo10 alloys , 2017 .

[73]  Tresa M. Pollock,et al.  Strengthening Mechanisms in Polycrystalline Multimodal Nickel-Base Superalloys , 2009 .

[74]  Jonathan D. Poplawsky,et al.  Secondary phases in AlxCoCrFeNi high-entropy alloys: An in-situ TEM heating study and thermodynamic appraisal , 2017 .

[75]  J. Langford,et al.  Scherrer after sixty years: a survey and some new results in the determination of crystallite size , 1978 .

[76]  G. Eggeler,et al.  Microstructure evolution and critical stress for twinning in the CrMnFeCoNi high-entropy alloy , 2016 .

[77]  T. Ungár.  Microstructural parameters from X-ray diffraction peak broadening , 2004 .

[78]  Ke An,et al.  Phase‐Transformation Ductilization of Brittle High‐Entropy Alloys via Metastability Engineering , 2017, Advanced materials.

[79]  M. Zhang,et al.  Deformation Behavior of Al0.25CoCrFeNi High-Entropy Alloy after Recrystallization , 2017 .

[80]  T. Nieh,et al.  Effects of Al addition on structural evolution and tensile properties of the FeCoNiCrMn high-entropy alloy system , 2014 .

[81]  A. Kuznetsov,et al.  Effect of Mn and V on structure and mechanical properties of high-entropy alloys based on CoCrFeNi system , 2014 .

[82]  Wei Guo,et al.  The effect of carbon on the microstructures, mechanical properties, and deformation mechanisms of thermo-mechanically treated Fe 40.4 Ni 11.3 Mn 34.8 Al 7.5 Cr 6 high entropy alloys , 2017 .

[83]  I. Todd,et al.  The use of high-entropy alloys in additive manufacturing , 2015 .

[84]  K. An,et al.  A precipitation-hardened high-entropy alloy with outstanding tensile properties , 2016 .

[85]  C. Tasan,et al.  Design of a twinning-induced plasticity high entropy alloy , 2015 .

[86]  J. Lenkkeri.  The elastic moduli of some body-centred cubic titanium-vanadium, vanadium-chromium and chromium-iron alloys , 1980 .

[87]  K. Lu.  Stabilizing nanostructures in metals using grain and twin boundary architectures , 2016 .

[88]  A. Ruban,et al.  First-principles study of elastic properties of Cr- and Fe-rich Fe-Cr alloys , 2011 .

[89]  Jian Lu,et al.  Phase stability and tensile properties of Co-free Al0.5CrCuFeNi2 high-entropy alloys , 2014 .