Remelting Induced Fully-Equiaxed Microstructures with Anomalous Eutectics in the Additive Manufactured Ni 32Co 30Cr 10Fe 10Al 18 Eutectic High-Entropy Alloy

Abstract

Large columnar grains with epitaxial growth are commonly obtained in the additive manufacturing of metals, resulting in anisotropic mechanical properties and even hot-tearing cracks. Here, we demonstrate a new approach via remelting-introduced columnar-to-equiaxed transformation to promote the formation of fully-equiaxed microstructures in the additive manufacturing of Ni32Co30Cr10Fe10Al18 eutectic high-entropy alloy. Our present work displays promising isotropic mechanical properties with a superior combination of strength and ductility, compared to conventional as-cast and other as-printed eutectic high-entropy alloys. This novel finding could be applicable to the additive manufacturing of other eutectic systems for equiaxed microstructure control and performance optimization.