High-zirconium bulk metallic glasses with high strength and large ductility

In this paper, high-zirconium Zr 66+2 x Al 9− x (Ni 1/3 Cu 2/3 ) 25− x ( x =0,1,2 at.%) bulk metallic glasses with high strength and large ductility were fabricated by copper mould casting. The effects of zirconium content on the glass-forming ability (GFA), thermal properties and mechanical properties were investigated using X-ray diffractometer (XRD), differential scanning calorimeter (DSC), and mechanical testing system in compressive and three-point bending modes, respectively. The high-zirconium BMGs show the critical diameters of 3–5 mm, the supercooled liquid region ranging from 70 K to 99 K, and the yield strength of over 1700 MPa. The Zr 70 Al 7 (Ni 1/3 Cu 2/3 ) 23 BMG exhibits a large compressive plastic strain up to 21% and a high notch toughness value of 60.6 MPa m 1/2 . The increase in Zr content results in the decrease in GFA and thermostability, and in the improvement of plasticity under compressive and three-point bending conditions. The superior plasticity of high-zirconium BMGs is attributed to their high Poisson’s ratio and small elastic modulus ratio µ/ B .