Formation of Ni-Nb-Zr-X (X = Ti, Ta, Fe, Cu, Co) bulk metallic glasses

The effect of the fourth element on glass-forming ability (GFA) in Ni-Nb-Zr-X (X = Ti, Ta, Fe, Cu, Co, V, Y, Mo, Sn, Al, Si) bulk metallic glass (BMG) system has been studied. Among these elements, Co addition can increase GFA of the Ni-Nb-Zr BMG system. The best glass former is Ni57Nb33Zr5CO5 alloy with a critical diameter of 3.5 mm. The corrosion rate of this alloy is approximately one order of magnitude less than that of the stainless steel in aggressive 6 M HCl open to air at room temperature. This alloy exhibits high T-g of 866 K, supercooled liquid region Delta T-x of 45 K, compressive fracture strength of 2.9 GPa, 1% compressive plasticity, and excellent corrosion resistance as compared to stainless steel. The combination of high thermal stability, high strength with compressive plasticity and excellent corrosion resistance enables these alloys to have potential industrial applications. Furthermore, the addition of Sn to Ni-Nb-Zr-Co alloy is effective for enhancing the stability of supercooled liquid. The maximum supercooled liquid region of 85 K is obtained in Ni57CO5(Nb33/38Zr5/38)(33)Sn-5 BMG. (C) 2008 Elsevier B.V. All rights reserved.