Fig. 5: TEM diffraction patterns, intensity of MSRO-derived extra diffuse discs, and the associated STEM images for different strain rates.
From: Mechanically derived short-range order and its impact on the multi-principal-element alloys
Selected-area [\(\bar{1}\)12] TEM-EDPs taken from individual HEA grains: a before and b after tensile straining at different strain rates. These EDPs were acquired from the region of slip bands in each deformed specimen. Green arrows indicate periodic diffuse scattering along the {311} directions caused by MSRO. c Logarithmically scaled diffraction intensity along the red lines in a, b: that is, the diagonal lines across normal fcc {311} spots in the EDPs from HEA-L (black) and HEA-M (blue). The hump owing to MSRO-generated diffuse scattering in b is outlined by green arrows in the profiles. The measured diffraction intensity for the same alloy composition subjected to 77 K-tensile straining at έ = 10−3 (red; HEA-H) is also included. d Inverse STEM-FFT (left panel) and annular dark-field (right panels) images formed with the MSRO-introduced extra diffuse discs in the FFT or diffraction patterns (yellow dashed circles) in b. The bright contrast in the real microstructure shows the MSRO domains (green dashed circles) in the slip bands that form during straining. The magnified region (yellow box) of the STEM image revealed no shearing of the MSROs in the slip bands inclined to the <110> directions. e Histograms of identified MSROs diameters for HEA-L (grey) and HEA-M (blue) samples, showing the mean value d.
