Effects of Different Contents of Each Component on the Structural Stability and Mechanical Properties of Co-Cr-Fe-Ni High-Entropy Alloys

Haibo Liu,Chunqiang Zhuang,Lei Liu,Cunlin Xin

doi:10.3390/app11062832

Abstract

The structural stability of high-entropy alloys (HEAs) is closely related to their mechanical properties. The precise control of the component content is a key step toward understanding their structural stability and further determining their mechanical properties. In this study, first-principle calculations were performed to investigate the effects of different contents of each component on the structural stability and mechanical properties of Co-Cr-Fe-Ni HEAs based on the supercell model. Co-Cr-Fe-Ni HEAs were constructed based on a single face-centered cubic (FCC) solid solution. Elemental components have a clear effect on their structure and performance; the Cr and Fe elements have an obvious effect on the structural stability and equilibrium lattice constant, respectively. The Ni elements have an obvious effect on stiffness. The Pugh ratios indicate that Cr and Ni addition may increase ductility, whereas Co and Fe addition may decrease it. With increasing Co and Fe contents or decreasing Cr and Ni contents, the structural stability and stiffness of Co-Cr-Fe-Ni HEAs are improved. The structural stability and mechanical properties may be related to the strength of the metallic bonding and covalent bonding inside Co-Cr-Fe-Ni HEAs, which, in turn, is determined by the change in element content. Our results provide the underlying insights needed to guide the optimization of Co-Cr-Fe-Ni HEAs with excellent mechanical properties.

Highlights

High-entropy alloys (HEAs) have stimulated widespread interest due to their outstanding properties since they were independently proposed by Yeh and Cantor [1,2]
We used the special quasirandom supercell (SQS) [39] model based on empirical parameters and first-principle calculations to study the effect of the different content of each component on the structural and mechanical properties of Co-Cr-Fe-Ni HEAs
CIonncsluumsimonasry, we used a supercell model based on empirical parameters and firstprinciIpnlescuamlcmulaartyio, nwsetousteudday tshueperffceecltlsmoof deiflfebraesnetdcontenmtspiorficeaalcphacroammpetoenresnatnodnftihrsetstprruicntcuipralel sctaalbciuliltaytiaonnds mtoescthuadnyictahleperfofpecetrstioesf dofifCfeor-eCnrt-cFoen-NteinHtsEoAf se.aTchecovmalepnocneeenltecotnrotnhe costnrcuecntutrraatliosnta, beinlitthyalapnydomf mecihxainngic, aelnptrrooppyeortfiemsioxfinCgo, -aCtorm-Fiec-sNizieHdEifAfesr.eTnhce,vaanldenΩceinedleictartoen that the Co-Cr-Fe-Ni HEAs studied in this work may be a single face-centered cubic (FCC) solid-solution phase, and all alloys are mechanically stable at the ground state

Summary

Introduction

High-entropy alloys (HEAs) have stimulated widespread interest due to their outstanding properties since they were independently proposed by Yeh and Cantor [1,2]. For Co-Cr-Fe-Ni HEAs, there have been plenty of investigations on phase stability [9,10,11], local chemical ordering [12,13], mechanical [14,15,16,17,18], tribological [19,20,21], corrosion [22,23,24,25,26,27], and magnetic [28,29] and irradiation resistance [30,31] Most of these works are based on experimental observations. We used the special quasirandom supercell (SQS) [39] model based on empirical parameters and first-principle calculations to study the effect of the different content of each component on the structural and mechanical properties of Co-Cr-Fe-Ni HEAs. When one component percentage is determined, the other three atomic percentages are divided.

Computational Details

Mechanical Properties

Conclusions