Effect of Al-5Ti-B-RE Grain Refiner on the Microstructures and Properties of AlCuCoCrFeNi High Entropy Alloys

Abstract. A series of AlCrFeCoNiCu High-entropy Alloys added Al-5Ti-B-RE grain refiner were prepared by vacuum arc furnace. The microstructures of the series of as-cast AlCrFeCoNiCu alloys are typical dendrites and are constituted by two kinds of solid solution (αphase andβphase). αphase is body-centered cubic (bcc) structure composed of Al, Cr, Co, Fe, Ni and a few Cu, and βphase is face-centered cubic (fcc) which enriches Cu. With the increase of Al-5Ti-B-RE, the region ofαphase becomes larger. When the content of Al-5Ti-B-RE is 0.4%(wt), the volume ratio values of α phase increases, moreover, α phase and β phase evenly distribute, and either the compressive strength (2.28GPa) or the compressive ratio (20.95%) is maximized. Fan pattern appears in the fracture morphologies of these alloys, and it is cleavage fracture. These alloys belong to brittle materials