Fig. 1. (a) Schematic illustration of the preparation of nanoporous ultra-high-entropy alloys (np-UHEAs). (b) X-ray diffraction (XRD) patterns of as-made precursor alloy Al₈₇Ag₁Au₁Co₁Cu₁Fe₁Ir₁Mo₁Ni₁Pd₁Pt₁Rh₁Ru₁Ti₁ quenched by melt spinning to obtain ribbons and np-UHEA14 after dealloying. (c) Scanning electron microscopy (SEM) images of the cross-section regions of np-UHEA14. (d) Low-magnification transmission electron microscopy (TEM) image of np-UHEA14 showing nanoporosity of ∼50 nm and the corresponding selected-area diffraction pattern showing the fcc structure. (e) High-resolution TEM image showing small nanopores ∼5 nm in size and randomly oriented nanocrystallinity.