Influence of microgravity on spinodal decomposition in a binary metallic system

Kurzfassung

Processes of phase separation and phase segregation evolving through spontaneous growth of fluctuations, e.g., through fluctuations of concentration in liquid-liquid and solid-solid systems or fluctuations of density in gas-liquid systems are known as spinodal decomposition. In the present work we verify the role of forced convective flow arising in experiments on the Ground and its absence under microgravity on the spinodal decomposition in binary metallic undercooled liquid. To give interpretation of the observed non-equilibrium phenomena, we use a model of spinodal decomposition [1] which allows us to describe early and late stages of phase separation under arbitrary quenching depth into spinodal region of phase diagram. Main characteristics of the model (e.g., structure factor and amplification rate on spinodal decomposition) were investigated recently in details [2-4]. The model is extended for the case of forced convective flow and the dynamics of spinodal decomposition is modelled in one and three spatial dimensions using computational methods of solution of the hyperbolic differential equations. Using the model predictions, several verifications of spinodal decomposition under microgravity and on the Ground are established. We acknowledge support from DFG (German Research Foundation) under the Project No. HE 160/19 and DLR Space Management under contract 50WM1140.