Mechanical properties and failure mechanisms of Zr-based amorphous alloys with various element compositions under different strain rates

This study investigated the mechanical properties, glass-forming ability (GFA), and microstructural evolution of ZrCuAlNi amorphous alloys with various niobium (Nb) and silver (Ag) additions under static (1 x 10(-1) - 1 x 10(-3) s(-1)) and dynamic (3 x 10(3) - 5 x 10(3) s(-1)) loading conditions. The x-ray diffraction (XRD) results revealed that all of the alloys had an amorphous structure, and the GFA improved with an increasing Ag content. The Zr56Cu24Al9Ni7Nb1Ag3 alloy showed the highest flow stress among the various alloys under both strain rate ranges. For all of the alloys, the fracture strain increased with an increasing Ag content. Moreover, the strain rate sensitivity increased with increasing strain rate. The scanning electron microscopy observations showed that the fracture surfaces had a dimple structure. As the Ag content increased, the dimple structure changed from a smooth to molten appearance. In addition, the dimple structure density increased with an increasing strain rate. The results present that the ductility of the ZrCuAlNi amorphous alloys could be improved by increasing the Ag element content.