Effect of hydrostatic pressure on reinforcing bulk metallic glasses investigated by synchrotron radiation and molecular dynamics simulations

Volume change of bulk metallic glasses (BMGs) during the repeated loading and unloading was investigated using in situ high-pressure synchrotron diffraction. Molecular dynamics simulations, which were used for further research of the microstructure change, were presented on an approximately 5.0×105 atom sample of an amorphous Fe80P20 model. The results show that the first compression process includes irreversible annihilation of free volume and elastic volume change. The main form of annihilation of free volume is that smaller atoms are extruded into the larger atomic clearance. Hydrostatic pressure can make the microstructure of BMGs more stable and dense. As a result of the decrease in free volume, hardness and bulk modulus of BMGs treated with hydrostatic pressure are obviously improved.