A senary TiZrHfCuNiBe high entropy bulk metallic glass with large glass-forming ability

Abstract Most reported bulk metallic glasses (BMGs) contain multiple constituent elements but only one of them is the principal element. Here we report that a senary Ti 16.7 Zr 16.7 Hf 16.7 Cu 16.7 Ni 16.7 Be 16.7 high entropy bulk metallic glass (HE-BMG) with a critical diameter larger than 15 mm has been successfully prepared by copper mold casting. It shows that newly developed HE-BMG possesses large glass-forming ability, together with the supercooled liquid region Δ T (= T x − T g ), reduced glass transition temperature T rg (= T g / T l ) and γ parameter (= T x /( T g + T l )) of 70 K, 0.619 and 0.422, respectively. The present result indicates that high entropy alloys, even for senary alloys or metal–metal type, could also possess large glass-forming ability. And the present HE-BMG could serve as a model material for studying the fundamental issues both of high entropy alloys and bulk metallic glasses.