Quantification of microstructure in a eutectic high entropy alloy AlCoCrFeNi2.1
Journal article, 2019

Eutectic high entropy alloys (EHEAs) are a new class of metallic alloys with good mechanical properties at various temperatures. In the present investigation, microstructural parameters such as the volume fraction of two phases (FCC (L12) and BCC (B2)) forming the eutectic, the orientation relationship between these phases and interphase boundary spacings in as-cast EHEA AlCoCrFeNi2.1 were quantified using electron microscopy. It is found that the two phases have a Kurdjumov-Sachs orientation relationship, i.e., {111} fcc || {110} bcc and 〈110〉 fcc || 〈111〉 bcc . It is also found that both regular semi-coherent lamellar and irregular curved interphase boundaries are present within individual eutectic colonies. The habit planes for the semi-coherent lamellar interfaces are {224} and {123} for the FCC and BCC phases, respectively. Quantitative microstructural analysis shows that the ratio of volume fractions of the FCC and BCC phases within the regular lamellar regions differs to that within irregular regions, which suggests a local chemistry difference between the two regions. Finally, the solidification process of EHEAs is discussed, and possible ways to optimize the mechanical properties by microstructural design are suggested.

Author

Adrianna Lozinko

Chalmers, Industrial and Materials Science, Materials and manufacture

Oleg V. Mishin

Technical University of Denmark (DTU)

Tianbo Yu

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

Yubin Zhang

Technical University of Denmark (DTU)

IOP Conference Series: Materials Science and Engineering

17578981 (ISSN) 1757899X (eISSN)

Vol. 580 012039

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

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

Subject Categories

Metallurgy and Metallic Materials

Areas of Advance

Materials Science

DOI

10.1088/1757-899X/580/1/012039

More information

Latest update

2/3/2020 1