I am trying to determine an intermediate phase/compounds that will be formed and its fraction (if possible) as well as their sequence (If more than 1 phase) from its chemical composition (alloying elements added).
It is difficult to predict 100 percent. However to the extent binary equilibrium may be predicted. But if alloying is done, its very complicated. It depends on heat treatment and manufacturing processes
If your solidification is an equilibrium condition, then you can use the phase diagram to estimate the possible phases and fraction of them. However, the equilibrium condition may not be favorable for many casting or thin-film preparation. One way will be using Thermo-Calc software, which will give you an idea about the phases. (equilibrium and non-equilibrium (Scheil calculation) conditions).
As already proposed, the chemical conditions that may lead to the formation of intermetallic phases can be calculated using the Calphad method (Thermo-Calc package: software and databases). Some paraequilibrium conditions can be considered too using Scheil module or by suspending some phases. Regards