La-based bulk metallic glass failure analysis under static and dynamic loading

Abstract

Samples of La-based bulk metallic glass were tested under both static and dynamic compression, and their failure analysed. The strain rates imposed ranged from 10−4/s to 103/s. Quasi-static compression was performed using an Instron universal testing machine and dynamic compression was applied by means of a Split-Hopkinson Pressure Bar (SHPB). This study focuses on: (1) Shear band characteristics under static and dynamic compression. A high-speed optical camera was used to capture visual images of shear band initiation; fracture surfaces were also examined by SEM; (2) Modelling of shear band temperature evolution within the specimen, with the aid of high-speed infrared camera images, to capture the temperature profile of the shear bands; (3) Effect of strain rate on response of La-based BMG. It is postulated that the negative strain rate dependence observed arises from the non-uniform direction of stress within the material, and stress concentration inside specimens.