Effect of Laser Energy Density on Microstructures and Properties of Additively Manufactured AlCoCrFeNi2.1 Eutectic High-Entropy Alloy

Abstract

In the present study, AlCoCrFeNi_2.1 eutectic high-entropy alloy (EHEA) has been fabricated by laser melting deposition (LMD). The influence of laser energy density on microstructures, wear resistance and corrosion resistance of the alloy was systematically explored. The results indicate that the AlCoCrFeNi_2.1 EHEA exhibited lamellar eutectic microstructures with alternating FCC and BCC phases. With the increase in laser energy density, the alloy grain size, interlamellar spacing, and volume fraction of the FCC phase increased, while the hardness of the alloy decreased. Meanwhile, the tribological performance of the alloy deteriorated with increasing laser energy density, and the combined effects of abrasive wear and adhesive wear gradually became significant. In addition, increasing laser energy density from 18.2 to 25 J/mm² resulted in the increase in corrosion current density of the AlCoCrFeNi_2.1 EHEA from 6.36 × 10⁻⁸ to 3.02 × 10⁻⁷ A/cm² and the negative shift of corrosion potential from − 211 to − 292 mV (SCE). In summary, reducing laser energy density improved the wear and corrosion performance of the additively manufactured AlCoCrFeNi_2.1 EHEA.