Screw vs. edge dislocation strengthening in body-centered-cubic high entropy alloys and implications for guided alloy design

Body-centered-cubic (BCC) high entropy alloys (HEAs) can show exceptionally high strength up to high temperatures. Mechanistic theories are needed to guide alloy discovery within the immense multicomponent HEA compositional space. Here, two new theories for strengthening as controlled by screw and edge dislocations, respectively, are applied to predict the yield stresses of a range of BCC alloys over a wide range of temperatures. Results show that the screw theory, with one fitting parameter, can capture experiments in many dilute and non-dilute alloys while the parameter-free edge theory agrees with experiments in non-dilute alloys having a sufficiently large misfit parameter. These results indicate a transition in single-phase alloy strengthening from traditional screw dominance to edge dominance with increasing misfit that is enabled in complex non-dilute alloys. These results point to the use of the edge theory to guide design of high-temperature alloys in the non-dilute range.

[1]  C. Leinenbach,et al.  Theory-guided Design of High-strength, High-melting point, Ductile, Low-density, Single-phase BCC High Entropy Alloys , 2022, Acta Materialia.

[2]  W. Curtin,et al.  Screw-controlled strength of BCC non-dilute and High-Entropy alloys , 2022, Acta Materialia.

[3]  N. Stepanov,et al.  Cross-kink unpinning controls the medium- to high-temperature strength of body-centered cubic NbTiZr medium-entropy alloy , 2022, Scripta Materialia.

[4]  K. An,et al.  Strength can be controlled by edge dislocations in refractory high-entropy alloys , 2021, Nature Communications.

[5]  W. Curtin,et al.  High energy barriers for edge dislocation motion in body-centered cubic high entropy alloys , 2021, npj Computational Materials.

[6]  Hyunseok Oh,et al.  Optimization of conflicting properties via engineering compositional complexity in refractory high entropy alloys , 2021, Scripta Materialia.

[7]  Jingjing Li,et al.  Correlating Strength and Hardness of High‐Entropy Alloys , 2021, Advanced Engineering Materials.

[8]  B. Akdim,et al.  Theory of solid solution strengthening of BCC Chemically Complex Alloys , 2021 .

[9]  G. Moore,et al.  Anomalous collapses of Nares Strait ice arches leads to enhanced export of Arctic sea ice , 2021, Nature communications.

[10]  J. Schroers,et al.  Theoretical prediction of high melting temperature for a Mo–Ru–Ta–W HCP multiprincipal element alloy , 2021, npj Computational Materials.

[11]  I. Beyerlein,et al.  Multiplicity of dislocation pathways in a refractory multiprincipal element alloy , 2020, Science.

[12]  K. Chaput,et al.  Effect of Fe additions on the microstructure and properties of Nb-Mo-Ti alloys , 2020, International Journal of Refractory Metals and Hard Materials.

[13]  W. Curtin,et al.  Mechanistic origin of high strength in refractory BCC high entropy alloys up to 1900K , 2019, Acta Materialia.

[14]  W. Curtin,et al.  Theory of screw dislocation strengthening in random BCC alloys from dilute to “High-Entropy” alloys , 2020 .

[15]  K. Chaput,et al.  Ductile Nb alloys with reduced density and cost , 2019, Journal of Alloys and Compounds.

[16]  S. Gorsse,et al.  High temperature strength of refractory complex concentrated alloys , 2019, Acta Materialia.

[17]  Dierk Raabe,et al.  High-entropy alloys , 2019, Nature Reviews Materials.

[18]  C. Woodward,et al.  Modeling solution hardening in BCC refractory complex concentrated alloys: NbTiZr, Nb1.5TiZr0.5 and Nb0.5TiZr1.5 , 2019, Acta Materialia.

[19]  G. Dirras,et al.  Comprehensive data compilation on the mechanical properties of refractory high-entropy alloys , 2018, Data in brief.

[20]  M. Heilmaier,et al.  Contribution of Lattice Distortion to Solid Solution Strengthening in a Series of Refractory High Entropy Alloys , 2018, Metallurgical and Materials Transactions A.

[21]  Yi Wang,et al.  Solute-induced solid-solution softening and hardening in bcc tungsten , 2017 .

[22]  N. Chen,et al.  Effect of Ti additions on mechanical properties of NbMoTaW and VNbMoTaW refractory high entropy alloys , 2017 .

[23]  C. Draxl,et al.  Impact of d -band filling on the dislocation properties of bcc transition metals: The case of tantalum-tungsten alloys investigated by density-functional theory , 2017 .

[24]  J. Qiao,et al.  Mechanical properties of refractory high-entropy alloys: Experiments and modeling , 2017 .

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

[26]  William A. Curtin,et al.  Theory of strengthening in fcc high entropy alloys , 2016 .

[27]  W. Curtin,et al.  Average-atom interatomic potential for random alloys , 2016 .

[28]  I. Guillot,et al.  On the room temperature deformation mechanisms of a TiZrHfNbTa refractory high-entropy alloy , 2015 .

[29]  D. Rodney,et al.  First-principles prediction of kink-pair activation enthalpy on screw dislocations in bcc transition metals: V, Nb, Ta, Mo, W, and Fe , 2015 .

[30]  Jien-Wei Yeh,et al.  High-Entropy Alloys , 2014 .

[31]  L. Kubin,et al.  Dislocations, Mesoscale Simulations and Plastic Flow , 2013 .

[32]  D. Caillard.  A TEM in situ study of alloying effects in iron. II—Solid solution hardening caused by high concentrations of Si and Cr , 2013 .

[33]  Zhe-feng Zhang,et al.  General relationship between strength and hardness , 2011 .

[34]  D. Miracle,et al.  Mechanical properties of Nb25Mo25Ta25W25 and V20Nb20Mo20Ta20W20 refractory high entropy alloys , 2011 .

[35]  C. J. Tyne,et al.  Correlation of Yield Strength and Tensile Strength with Hardness for Steels , 2008, Journal of Materials Engineering and Performance.

[36]  Andrew P. Horsfield,et al.  Self-interstitial atom defects in bcc transition metals: Group-specific trends , 2006 .

[37]  R. Johnson,et al.  Misfit-energy-increasing dislocations in vapor-deposited CoFe/NiFe multilayers , 2004 .

[38]  L. Höglund,et al.  Thermo-Calc & DICTRA, computational tools for materials science , 2002 .

[39]  Aamir Shabbir,et al.  Experiments and Modeling , 1991 .

[40]  D. Read.  Metallurgical effects in niobium-titanium alloys , 1978 .

[41]  R. Scattergood,et al.  The Orowan mechanism in anisotropic crystals , 1975 .

[42]  D. Tabor.  Hardness of Metals , 1937, Nature.