The Influence of Complex Thermal Treatment on the Mechanical Properties of Amorphous Materials

Metallic glass is a useful amorphous material with many industrial applications. How to improve its mechanical properties and understand its microscopic process details are still needed to be explored. In this master thesis, we investigate how potential energy, stress overshoot, elastic modulus, atomic displacement of metallic glass response to the external periodic thermal treatments and different initial preparation cooling rates. The whole works are computational, we use molecular dynamics (MD) simulation method to perform all the tasks. MD simulation could provide some information that hard to do experimentally. We found that in comparison with aged samples, thermal cycling treatment leads to more relaxed states with lower potential energy. There is a non-monotonic relation between external thermal amplitude and potential energy because of pre-melt of the metallic glass samples. Also simulation results indicate an inverse correlation between the potential energy and values of the elastic modulus as well as yield stress, as a function of the thermal amplitude. The larger thermal amplitude always increase the atomic displacement, no matter if the structure is stable.