Structure motif of chemical short-range order in a medium-entropy alloy

Abstract

The chemical short-range orders (CSRO) are the sub-nanosized entities inherent in high-/medium-entropy alloys (H/MEA). To discern CSRO poses the challenge with pending issues as to under what zone axis in electron diffraction, signature scattering specific to CSRO will appear and what the structure motif of CSRO is. Here, we show extra diffuse scattering by CSRO from [111] and [112] directions in a VCoNi MEA and accordingly, construct the $ \textrm{L}{1_1} $ -type structure motif, and derive the spacial shape of flat cuboid of CSRO in virtue of diffractions under varying zone axis. Moreover, we demonstrate the methods to identify CSRO in lattice images.

Keywords

• chemical short-range order
• electron diffraction
• unit cell
• medium-entropy alloy