Solvus line

A solvus line is a boundary in a phase diagram that indicates the conditions (such as temperature and composition) where a single solid material can separate into two different phases. In other words, it marks the limit below which a homogeneous alloy becomes unstable and begins to divide into two distinct parts with different compositions. Crossing the solvus line means the material can no longer stay uniform and starts to develop separate regions, which is important in understanding how materials change and behave during cooling or processing.