Elucidating the effect of cyclic closed-die forging processing on the microstructure and wear properties of novel low-cost [FeNi]_75−xCr₁₅Mn₁₀Nb_x (x = 0, 5, 10 at%) high-entropy alloys

For the first time, cyclic closed-die forging (CCDF) processing was used to process novel low-cost [FeNi]_75−xCr₁₅Mn₁₀Nb_x (x = 0, 5, 10 at%) high-entropy alloys (HEAs). These HEAs have a dual-phase structure with [FeNiNb]-rich dendrites dispersed in a nearly homogenous face-centered cubic (FCC) matrix. The increase in Nb leads to a higher fraction of [FeNiNb]-rich phase. Additionally, the [FeNi]₆₅Cr₁₅Mn₁₀Nb₁₀ alloy showed the development of homogenous nanograin, accumulation of dislocations, fragmentation of [FeNiNb]-rich dendrites, and efficient distribution within the matrix, resulting in ultrahigh hardness and the lowest wear rate, specifically 795 HV and (1.1 ± 0.1) × 10^–5 mm³.N⁻¹.m⁻¹ after CCDF. These findings suggest that CCDF processing has the potential to achieve cost-effective nanostructured HEAs and implement them in engineering and structural applications.