Abstract
Diamond-reinforced FeNiCrCuAl high-entropy alloys were fabricated by spark plasma sintering with 7 wt.% diamond. Titanium and chromium coatings were deposited on diamond surfaces via vacuum micro-evaporation, forming carbide coatings. FeNiCrCuAl HEA powders synthesized by gas atomization consist of a BCC solid solution phase and an AlNi phase. An FCC phase was observed in the SPS samples. Graphite phase was detected in the diamond-containing samples. The diamond surface coating significantly reduces the concentration of the graphite phase in the HEA matrix and contributes to the formation of metallurgical bonding between diamond and HEA matrix. Uncoated diamonds enhanced matrix hardness from 432.4 to 479.7 HV_0.5 through solid solution strengthening. Ti-coated diamonds exhibited optimal interfacial bonding, preserving bending strength at 410.0 MPa. Wear failure modes involved diamond spalling and matrix abrasion. Notably, Cr-coated diamond/HEA demonstrated superior wear resistance with an average friction coefficient of 0.15, attributed to thicker carbide-rich transition layers.

Key words
high-entropy alloys, diamond, interface bonding, solid-solution strengthening

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