Effects of sample diameter, aspect ratio, and strain rate on compressive deformation and fracture behavior of Zr50Cu34Al8Ag8 metallic glass

Abstract

In this paper, Zr50Cu34Al8Ag8 metallic glass bars with diameters of 2, 3, and 4 mm were prepared by copper mold suction casting. The compressive mechanical properties of metallic glass samples having different diameters, aspect ratios, and strain rates were tested by a universal testing machine. The microstructure of metallic glass samples was analyzed by X-ray diffractometer, scanning electron microscope, and transmission electron microscope. The experimental results show that the mechanical properties of Zr50Cu34Al8Ag8 metallic glass improve with decreasing sample diameter, aspect ratio, and strain rate. The maximum compressive strength, ultimate strain, and plastic strain of 1991.2 MPa, 7.95%, and 4.99% were respectively achieved for the metallic glass sample of φ = 2 mm. The main reason for the metallic glass's superior mechanical properties is its higher free volume content. For the metallic glass samples with the same diameter and different aspect ratios, the compressive strength and ultimate strain of the metallic glass with φ = 3 mm and aspect ratio = 1 is the largest, which are 2052.8 MPa and 15.2%, respectively, and the plastic strain is 11.09%. The improvement of mechanical properties of metallic glass samples is primarily attributed to the change of stress state. When the strain rate is 3 × 10−4 s, the compressive strength and ultimate strain of the sample are 1851.2 MPa and 4.09% respectively. This study will help to improve our understanding of the compression deformation and fracture behavior of metallic glasses, as well as promote their application.