1. The problem statement, all variables and given/known data 2. Relevant equations None. 3. The attempt at a solution This is the final part of a past exam question. I've got through the first parts and can (thanks to a seperate question I asked here) read the phase diagrams and find melting points etc. However now it's asking for "composition trajectories", "phase morphology" and "domain size and internal structure" and I'm completely lost. I can work out the molar proportions and compostions by drawing a line down the diagram at 22% and figuring the ratio at 42 degrees. But I have no idea what to do for the above quoted terms. Any guidance would really be appreciated, I'm completely at a loss how you would derive this information from the phase diagrams given.