Tensile fracture characteristics and deformation behavior of a Zr-based bulk metallic glass at high temperatures

The fracture characteristics of the Zr41.25Ti13.75Ni10Cu12.5Be22.5 (at.%) bulk metallic glass subjected to tensile tests at room temperature, the calorimetric glass transition temperature, and in the supercooled liquid region have been studied. The fracture behavior at high temperatures under tension deformation can be classified as three modes, i.e. brittle fracture, necking fracture and sustainable deformation, which strongly depend on the test temperature and strain rates. Typical vein-like structures are dominant on the brittle fracture surfaces at high temperatures while cleavage veins with round-cores are observed at room temperature. The high-temperature deformation behavior and the underlying controlling mechanisms are discussed in the frame of the 'free volume' theory.