Decoupling thermal and mechanical effects on metallic glasses creep

The creep behavior of metallic glasses (MGs) is intricately linked to the microstructural evolution, with atomic movement modes and mechanisms playing a crucial role in determining deformation characteristics. This study innovatively employs the Stepped Isothermal Method (SIM) to investigate the correlation between thermal activation and mechanical stimulus in MGs during creep deformation. By incrementally increasing temperature within a short time, SIM accelerates the creep process. The time-temperature-stress equivalence principle was used to analyze structural relaxation and predicting long-term performance. The experimental results demonstrated that the atomic diffusion rate and strain accumulation during the creep process are closely associated with the β relaxation process of MGs which is linked to the local motion and rearrangement of atoms. The results of activation energy per unit activation volume as a function of stress and temperature provide a deep understanding of the relationship between thermal activation and mechanical effects during creep deformation. The findings highlight the dominant role of thermal activation and the significant influence of mechanical stimulation. They also establish the relationship between these factors and β relaxation, shedding light on the underlying mechanisms driving creep in MGs. This work provides novel insights into the fundamental behavior of MGs under thermomechanical treatments. It also introduces a comprehensive methodology for evaluating long-term mechanical properties, advancing the development of high-performance materials for engineering applications.