Microstructure, Mechanical and Wear Resistance Properties of AlCoCrFeNi2.1-xNi3Al Eutectic High-Entropy Alloy Matrix Composites

Abstract

AlCoCrFeNi_2.1-xNi₃Al (x = 0, 5.0, 7.5, and 10 wt%, denoted as Ni₃Al0, Ni₃Al5.0, Ni₃Al7.5, and Ni₃Al10) eutectic high-entropy alloy (EHEA) matrix composites were fabricated by mechanical alloying and spark plasma sintering methods. The effects of Ni₃Al content on the microstructures, mechanical and wear properties of AlCoCrFeNi_2.1 EHEA were investigated. The results indicate that the AlCoCrFeNi_2.1-xNi₃Al composites present cellular grid morphologies composing of FCC/Ll₂ and B2 phases, and a small amount of Al₂O₃ and Cr₇C₃ phases. The addition of Ni₃Al significantly enhanced the compressive yield strength, compressive fracture strength, compressive strain and wear properties of the AlCoCrFeNi_2.1 composites. In particular, the Ni₃Al10 composite exhibits excellent comprehensive mechanical properties. The compressive yield strength, compressive fracture strength and compressive strain of the Ni₃Al10 composite, are 1845 MPa, 2301 MPa and 10.1%, respectively. The friction coefficient, wear width and depth, and mass loss of the Ni₃Al10 composite were 0.40, 0.9 mm, 20.5 mm, 0.016 g, respectively. Moreover, the wear mechanism of the Ni₃Al10 composite is major abrasive wear with a small amount of adhesive wear.