Exploring the evolutionary behavior of grain boundaries in titanium induced by temperature fluctuations using a combination of molecular dynamics simulations and experiments

Temperature fluctuation in low-temperature range is common environmental condition experienced by precision instruments. However, the effect of temperature fluctuation on grain boundary, which correlated with the mechanical and thermodynamics of materials, has not been elucidated. In this study, we used molecular dynamics to simulate the evolutionary behavior of grain boundary during temperature fluctuations. Unexpectedly, we found irreversible structural transformation in grain boundaries that experienced temperature fluctuations of low temperature range (<100 °C) and then returned to the initial temperature. Subsequently, we explored its influence on the macroscopic properties of material by experiments. The results show that structural transformation of grain boundary leads to a decrease in misorientation of grain boundary and macro size of material. Moreover, our experiments also show that structural transformation of grain boundary induced by temperature fluctuations is accomplished through the migration of atoms around grain boundary. It provides insight to investigate temperature dependence of grain boundary.