Structure and properties of Ni-60(Nb100-xTax)(34)Sn-6 bulk metallic glass alloys

Abstract

Refractory bulk metallic glasses and bulk metallic glass composites are formed in quaternary Ni-Nb-Ta-Sn alloy system. Alloys of composition Ni-60(Nb100-xTax)(34)Sn-6 (x = 20, 40, 60, 80) alloys were prepared by injection-casting the molten alloys into copper molds. Glassy alloys are formed in the thickness of half mm strips. With thicker strips (e.g., 1 mm), Nb2O5 and Ni3Sn phases and the amorphous phase form an in situ composite. Glass transition temperatures, crystallization temperatures, and Delta T-x, defined as T-x1 - T-g (T-x1: first crystallization temperature, T-g: glass transition temperature) of the alloys increase dramatically with increasing Ta contents. These refractory bulk amorphous alloys exhibit high Young's modulus (155-170 GPa), shear modulus (56-63 GPa), and estimated yield strength (3-3.6 GPa). (c) 2006 Elsevier B.V. All rights reserved.