Microstructure and Properties of AlCoCrFeNi2.1Nbx High‐Entropy Alloys Prepared by Selective Laser Melting

Abstract

In this study, Nb element was introduced into the AlCoCrFeNi2.1 eutectic high‐entropy alloy to create a heterogeneous structure. AlCoCrFeNi2.1Nbx (x=0, 0.25, 0.5) eutectic high‐entropy alloys were fabricated using selective laser melting technology. The forming characteristics, microstructure, and mechanical properties of the AlCoCrFeNi2.1Nbx eutectic high‐entropy alloys were investigated. The results showed that the relative density of the samples increased and then decreased. The optimal process parameters were determined as laser power of 50 W, scanning speed of 400 mm/s, scanning spacing of 70 μm, and layer thickness of 30 μm. The primary microstructure of AlCoCrFeNi2.1Nbx alloys (x>0) consisted of a hypoeutectic structure comprising BCC, FCC, and Fe2Nb‐type Laves phases. With the addition of Nb element, the hardness of the high‐entropy alloy increased from 600.6 HV to 774 HV, the yield strength increased from 664.1 MPa to 1091.9 MPa, while the ductility slightly decreased. Furthermore, the strengthening mechanisms of the alloy were attributed to the precipitation strengthening and solid solution strengthening of the Laves phase, as well as the grain refinement effect. The wear resistance of the alloy improved gradually with the increasing Nb content, and AlCoCrFeNi2.1Nb0.5 exhibited the best wear resistance, primarily through adhesive wear.This article is protected by copyright. All rights reserved.