High-Entropy Alloys: A Current Evaluation of Founding Ideas and Core Effects and Exploring “Nonlinear Alloys”

The burgeoning field of high-entropy alloys (HEAs) is underpinned by two foundational concepts, and early research has been motivated by several hypotheses known as “core effects.” The field is now entering its teenage years, and sufficient data have been collected to evaluate these hypotheses and to take a fresh look at the foundational concepts. Although recent assessments have concluded that two of the four HEA hypotheses are not supported by available data, new studies are already coming online to extend these analyses, and new interpretations are inspiring new directions for research within the field. This article gives an up-to-date evaluation of the HEA “core effects” and proposes “nonlinear alloys” as a new strategy to embrace the founding concept of compositional and microstructural vastness.

[1]  R. Hultgren,et al.  Selected Values of Thermodynamic Properties of Metals and Alloys , 1963 .

[2]  K. Kulkarni,et al.  Investigations of quaternary interdiffusion in a constituent system of high entropy alloys , 2015 .

[3]  Jien-Wei Yeh,et al.  Nanostructured nitride films of multi-element high-entropy alloys by reactive DC sputtering , 2004 .

[4]  Irving R Epstein,et al.  Cross-diffusion and pattern formation in reaction-diffusion systems. , 2009, Physical chemistry chemical physics : PCCP.

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

[6]  Jacob L. Jones,et al.  Entropy-stabilized oxides , 2015, Nature Communications.

[7]  Ralph Spolenak,et al.  Size-dependent plasticity in an Nb25Mo25Ta25W25 refractory high-entropy alloy , 2014 .

[8]  T. Chin,et al.  Formation of simple crystal structures in Cu-Co-Ni-Cr-Al-Fe-Ti-V alloys with multiprincipal metallic elements , 2004 .

[9]  B. S. Murty,et al.  Ni tracer diffusion in CoCrFeNi and CoCrFeMnNi high entropy alloys , 2016 .

[10]  B. Cantor,et al.  Microstructural development in equiatomic multicomponent alloys , 2004 .

[11]  Michael F. Ashby,et al.  Correlations for diffusion constants , 1980 .

[12]  C. Liu,et al.  More than entropy in high-entropy alloys: Forming solid solutions or amorphous phase , 2013 .

[13]  S. Fries,et al.  Compilation of `CALPHAD' formation enthalpy data: Binary intermetallic compounds in the COST 507 Gibbsian database , 1998 .

[14]  Herbert Malamud,et al.  Landolt-Bornstein: Numerical Data and Functional Relationships in Science and Technology , 1985 .

[15]  T. Shun,et al.  Multi‐Principal‐Element Alloys with Improved Oxidation and Wear Resistance for Thermal Spray Coating , 2004 .

[16]  Yong Zhang,et al.  Prediction of high-entropy stabilized solid-solution in multi-component alloys , 2012 .

[17]  菊池 潮美.  Cohesion in Metals, Transition Metal alloys, F.R.de Boer,R.Boom,W.C.M.Mattens,A.R.Miedema,A.K.Niessen(共著), F.R de boer,D.G.pettifor編Cohesion and Structure Vol.1, 1989年, North-Holland発行, 23×15.5cm, 758ページ, Dfl.250 , 1990 .

[18]  J. Yeh,et al.  Wear resistance and high-temperature compression strength of Fcc CuCoNiCrAl0.5Fe alloy with boron addition , 2004 .

[19]  J. Yeh,et al.  Interdiffusion in the FCC-structured Al-Co-Cr-Fe-Ni high entropy alloys: Experimental studies and numerical simulations , 2016 .

[20]  J. Yeh.  Recent progress in high-entropy alloys , 2006 .

[21]  O. J. Kleppa,et al.  The standard enthalpies of formation of the compounds of early transition metals with late transition metals and with noble metals as determined by Kleppa and co-workers at the University of Chicago : A review , 2001 .

[22]  A. Takeuchi,et al.  Mixing enthalpy of liquid phase calculated by miedema’s scheme and approximated with sub-regular solution model for assessing forming ability of amorphous and glassy alloys , 2010 .

[23]  Michael D. Uchic,et al.  Exploration and Development of High Entropy Alloys for Structural Applications , 2014, Entropy.

[24]  J. Yeh,et al.  Sluggish diffusion in Co-Cr-Fe-Mn-Ni high-entropy alloys , 2013 .

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

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

[27]  D. Beke,et al.  On the diffusion in high-entropy alloys , 2016, Materials Letters.

[28]  P. Liaw,et al.  Solid‐Solution Phase Formation Rules for Multi‐component Alloys , 2008 .

[29]  F. D. Boer.  Cohesion in Metals: Transition Metal Alloys , 1989 .

[30]  J. Howell,et al.  Diffusion in Solids , 1984, Materials Science Forum.

[31]  C. Woodward,et al.  Accelerated exploration of multi-principal element alloys with solid solution phases , 2015, Nature Communications.

[32]  C. Colinet.  The thermodynamic properties of rare earth metallic systems , 1995 .

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

[34]  H. Bei,et al.  Relative effects of enthalpy and entropy on the phase stability of equiatomic high-entropy alloys , 2013 .