LAUSR

Abstract Metallic glasses (MGs) are advanced alloys possessing an amorphous structure and a host of properties (e.g., theoretical-limit-approaching strength) far superior to conventional crystalline metals/alloys. Hafnium-based MGs (HBMGs) have the additional advantage of high density, desirable for critical applications such as kinetic energy penetrators. HBMGs have still limited glass-forming ability (GFA), with a critical casting diameter/thickness (Dc) ≤10 mm, beyond which crystallization will occur. We report our discovery of two HBMGs, Hf40Zr9Cu31Ni8Al12 and Hf43Zr4Cu31.25Ni9.75Al12 possessing a Dc of 18 mm which nearly doubles the current record and enables notably bigger products and easier manufacturing/processing of HBMGs. Both alloys possess a density above 10.2 g/cm3, higher than most MGs based on other elements (e.g., Fe, Cu). They also stand out from most other MGs with a high T rg >0.61, high γ -parameter>0.42 and high atomic packing efficiency>0.8. We also report their thermal and mechanical properties and discuss the factors that may have contributed to their exceptional GFA.