Microstructural characterization of eutectic and near-eutectic AlCoCrFeNi high-entropy alloys
Journal article, 2020

The microstructure and orientation relationships in five AlCoCrFeNix alloys with eutectic (x = 2.1) and near-eutectic compositions (x = 1.9, 2.0, 2.2 and 2.3) have been characterized in this work. The eutectic and near-eutectic AlCoCrFeNix alloys have microstructures consisting of face-centered cubic (FCC) and ordered body-centered cubic (BCC) B2 phases, where the volume fraction of the FCC phase is found to increase with increasing Ni content. It is found that each eutectic colony consists of several parallel lamellae in the colony center and peripheral irregular labyrinth-like structures. The frequency of the irregular structures appears to be higher in the near-eutectic alloys than in the eutectic alloy. The ratio of the average widths of FCC and BCC lamellae is observed to be sensitive to the chemical composition and increases with the increasing Ni content. The two phases in the studied alloys display relationships close to the Kurdjumov-Sachs orientation relationship. The distribution of misorientation angles between the interphase boundaries changes as a function of the Ni content. The result of this change is a small increase in the average misorientation angle across the FCC/BCC interphase boundaries with increasing Ni content. The differences in the morphological crystallographic characteristics between the alloys are briefly discussed.

Eutectic alloys

High-entropy alloys

EBSD

Orientation relationship

Solidification microstructure

Author

Adrianna Lozinko

Chalmers, Industrial and Materials Science, Materials and manufacture

Yubin Zhang

Technical University of Denmark (DTU)

Oleg V. Mishin

Technical University of Denmark (DTU)

Uta Klement

Chalmers, Industrial and Materials Science, Materials and manufacture

Sheng Guo

Chalmers, Industrial and Materials Science, Materials and manufacture

Journal of Alloys and Compounds

0925-8388 (ISSN)

Vol. 822 153558

Eutectic high entropy alloys: a promising new class of high temperature alloys

Swedish Research Council (VR), 2016-01-01 -- 2020-12-31.

Subject Categories

Other Materials Engineering

Metallurgy and Metallic Materials

Areas of Advance

Materials Science

DOI

10.1016/j.jallcom.2019.153558

More information

Latest update

2/10/2020