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<p>The microstructure and the mechanical and tribological properties of high-entropy alloys (HEAs) within the CoCrFeMnNi system with varying elemental ratios are investigated. Five alloys with different Co contents (15–25 at.%), Cr (15–25 at.%), Fe (10–30 at.%), and Mn (10–30 at.%), alongside a&#xa0;fixed Ni concentration (20&#xa0;at.%), are fabricated via vacuum induction melting. An X‑ray spectral microanalysis conducted by scanning electron microscopy (SEM) reveals a&#xa0;dendritic microstructure predominantly composed of a&#xa0;face-centered cubic (FCC) phase. Nanoscale secondary MnNi phases are identified in the alloys with elevated manganese content (exceeding 25%), which are localized along the grain boundaries. The equiatomic Co<sub>2</sub>₀Cr<sub>2</sub>₀Fe<sub>2</sub>₀Mn<sub>2</sub>₀Ni<sub>2</sub>₀ alloy exhibits the highest nanohardness (2.06 GPa) and Young’s modulus (109 GPa) values attributed to the synergistic interplay of the solid-solution strengthening and high dislocation density. The microhardness values range from 121 to 146 HV, peaking in the alloy with 30% Mn (Co<sub>2</sub>₀Cr<sub>2</sub>₀Fe<sub>1</sub>₀Mn<sub>3</sub>₀Ni<sub>2</sub>₀). The tribological tests performed under a&#xa0;pin-on-disc configuration demonstrate a&#xa0;direct correlation between the coefficient of friction (0.663–0.824) and the wear rate ((5.8–8.7)⋅10⁻<sup>5</sup> mm<sup>3</sup>/N·m). The minimum wear rate is recorded for the Co<sub>25</sub>Cr<sub>25</sub>Fe<sub>19</sub>Mn<sub>15</sub>Ni<sub>2</sub>₀ alloy (5.8⋅10⁻<sup>5</sup> mm<sup>3</sup>/N·m), resulting from the formation of protective Cr<sub>2</sub>O<sub>3</sub>/MnO<sub>2</sub> oxide layers mitigating adhesion. An optimal balance of strength and wear resistance is achieved in the equiatomic composition, which demonstrates a&#xa0;wear rate of 6.1⋅10⁻<sup>5</sup> mm<sup>3</sup>/N·m and a&#xa0;coefficient of friction of 0.743.</p>

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Structural and mechanical characteristics of high-entropy CoCrFeMnNi alloys manufactured by vacuum induction melting

  • 期刊论文

  • 发表日期：

    2026年1月21日

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  • V. K. Drobyshev,
  • I. A. Panchenko,
  • S. V. Konovalov,
  • E. M. Zapolskaya

摘要

The microstructure and the mechanical and tribological properties of high-entropy alloys (HEAs) within the CoCrFeMnNi system with varying elemental ratios are investigated. Five alloys with different Co contents (15–25 at.%), Cr (15–25 at.%), Fe (10–30 at.%), and Mn (10–30 at.%), alongside a fixed Ni concentration (20 at.%), are fabricated via vacuum induction melting. An X‑ray spectral microanalysis conducted by scanning electron microscopy (SEM) reveals a dendritic microstructure predominantly composed of a face-centered cubic (FCC) phase. Nanoscale secondary MnNi phases are identified in the alloys with elevated manganese content (exceeding 25%), which are localized along the grain boundaries. The equiatomic Co2₀Cr2₀Fe2₀Mn2₀Ni2₀ alloy exhibits the highest nanohardness (2.06 GPa) and Young’s modulus (109 GPa) values attributed to the synergistic interplay of the solid-solution strengthening and high dislocation density. The microhardness values range from 121 to 146 HV, peaking in the alloy with 30% Mn (Co2₀Cr2₀Fe1₀Mn3₀Ni2₀). The tribological tests performed under a pin-on-disc configuration demonstrate a direct correlation between the coefficient of friction (0.663–0.824) and the wear rate ((5.8–8.7)⋅10⁻5 mm3/N·m). The minimum wear rate is recorded for the Co25Cr25Fe19Mn15Ni2₀ alloy (5.8⋅10⁻5 mm3/N·m), resulting from the formation of protective Cr2O3/MnO2 oxide layers mitigating adhesion. An optimal balance of strength and wear resistance is achieved in the equiatomic composition, which demonstrates a wear rate of 6.1⋅10⁻5 mm3/N·m and a coefficient of friction of 0.743.