Fig. 3. The microstructure evolution in the medium-entropy Al_0.2CoNiV alloy heat-treated at 800 °C for 1 h.

a Electron backscatter diffraction (EBSD) images showing quality (IQ), b kernel average misorientation (KAM), inverse pole figure (IPF) maps of c face-centered-cubic (FCC) and d L2₁ phases. e Electron-channeling contrast imaging (ECCI) map, f transmission electron microscopy (TEM) image of micro-shear bands and L2₁ particles in the non-recrystallized FCC grains. g, h High-resolution TEM and corresponding fast Fourier-transform (FFT) images indicate the micro-shear band consists of stacking faults and nanotwins. i Atom probe tomography (APT) tip reconstruction and 1-D profile across the L2₁ and FCC matrix. The phase boundary is highlighted by a 7.5 at% Al iso-concentration surface. Each datum point stands for an average concentration measured at a 0.5 nm interval, where error bars indicate a standard deviation.