Fig. 4: Mechanical and tribological properties of the interlocked Cu-Fe-based composite.

a Microhardness profiles measured from the sample surface inwards for the UHSQ-processed composite, UHS-processed composite, and pure Cu. The shaded bands represent the standard deviation of the measurements. b Representative microhardness line scan across the Cu matrix, the Cu-Fe interface, and multi-phase nanocrystals. c The plot of microhardness versus electrical conductivity (% IACS), benchmarking the UHSQ-processed composite against various material classes reported in the literature^{22,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55}. (The colored background regions categorize different material systems: the pale pink region represents Cu-based alloys, the pale cyan region represents metallic glasses and ceramics, and the pale purple region corresponds to the W-Cu alloy family). d Wear test results showing the wear loss rate as a function of friction cycles under a load of 10 MPa and a sliding speed of 500 r/min. e Optical micrographs of the worn surfaces of UHSQ-processed composites with 25 vol% and 50 vol% Fe₅₅Cr₂₅Mo₁₆B₂C₂ metallic glass, showing uniform wear tracks. f High-magnification SEM images tracking the morphology of multi-phase nanocrystals on the wear surface after 15 and 60 minutes of sliding.