Crystallization kinetics and mechanical properties of Zr56Cu24Al9Ni7-xTi4Agx (x = 0, 1, 3, 5, and 7) metallic glasses

Abstract

The effect of the replacement of Ni with Ag on the crystallization kinetics and mechanical properties of Zr56Cu24Al9Ni7-xTi4Agx (x = 0, 1, 3, 5, and 7 at.%) metallic glasses were investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and microhardness/compressive testing. Proper Ag substitution significantly improved of the glass-forming ability, crystallization activation energy, and mechanical properties of these materials. The critical diameter increased to 6–8 mm for Ag contents of 1, 3, and 5 at.%. The Ag-containing glassy alloys displayed higher crystallization activation energies than their Ag-free counterparts, suggesting that proper substitution hindered crystallization. The specimens of 3 mm in diameter and a Ag content of 1 at.% showed the largest strain under compression (ca. 4.68 ± 0.03%) and fracture strength (up to 1826 ± 31 MPa). A combination of veins and droplets was observed on the compressive fracture surfaces of the alloys. Furthermore, the fracture mechanisms, which enhanced the plasticity of the alloys, were also discussed herein.