Design of Eutectic High Entropy Alloys in Al–Co–Cr–Fe–Ni System

Abstract

In the present work, a simple approach is proposed for predicting the compositions of eutectic high entropy alloys (EHEAs) in Al-Co-Cr-Fe-Ni system. It is proposed that eutectic lines exist between certain eutectic alloys in this system and, as a result, new eutectic or near-eutectic compositions can be obtained by mixing the alloys which are located on the same eutectic line. The approach is applied for a series of experimentally verified eutectic alloys and new eutectic or near-eutectic alloys are designed for Al-Co-Cr-Fe-Ni system. Furthermore, by investigating the compositions of verified eutectic alloys in Al-Co-Cr-Fe-Ni system, compositional diagrams are proposed which show the relations between the concentrations of constituent elements in eutectic alloys. The compositional diagrams suggest that EHEAs are derived from binary and ternary eutectic alloys.Moreover, the proposed diagrams can be considered as convenient methods for evaluating the composition of EHEAs in Al-Co-Cr-Fe-Ni system.

Investigations of Oxide Dispersoids and Annealing on Characteristics of AlCoCrFeNi2.1 Coatings and Bulks Prepared by Mechanical Alloying

“…It has been reported that the formation of a new BCC phase in the AlxCoCrFeNi alloy system can be associated with the lattice distortion induced by the atomic size difference [3]. In recent years, eutectic high-entropy alloys (EHEAs) have emerged as one of the most popular classes of HEAs as they exhibit a nano-lamellar eutectic microstructure composed of BCC and FCC phases, which improve the material's strength, ductility, and microstructure stability [6][7][8]. It was proposed by Lu et al in 2014 [9] that an as-cast AlCoCrFeNi 2.1 comprising the CoCrFe phase (ductile FCC phase) and the NiAl phase (high-strength B2 phase) demonstrates promising properties with excellent strength (1186 MPa) and ductility (22.8%) [9].…”

Rapid screening of high-entropy alloys using neural networks and constituent elements

“…HEAs have come to be defined as multi-principal element alloys (MPEAs) with at least five elements all having equal, or near-equal, atomic ratios [1][2][3][4]. The consensus is also that HEAs form random single-phase solid solutions [5,6], although various dual-phase HEAs have been accepted [7][8][9]. Whether a HEA is single or dual-phase, the underlying lattices are generally highsymmetry, simple-solid solutions such as face-centered-cubic (FCC), body-centered-cubic (BCC) or hexagonal close-packed (HCP) [10].…”