Materials Lecture 8 Partial Solubility

Question 1

What is partial solubility?

Answer 1

When there is a limit to the number of solute atoms which can dissolve into the lattice structure without forming a solid phase. Complete solid solubility can replace all solvent atoms with solute atoms and solid phase will remain the same (same crystallattuc structure.) Partial solubility thwre is a limit to the number of solute atoms you can add to the solvent lattice structure before the solute atoms form another solid phase (another crystal structure.)

Question 2

What is the eutectic temperature?

Answer 2

When a liquid solidifies into two different solid phases. Therefore eutectic point always on the liquidus line.

Question 3

At eutectic temp?

Answer 3

As two solid ohases start to form they have very different compositions (relative amounts of solute and solvent atoms) in each phase so the microstructure formed is lamellar (see slides Lecture 8 Partial Solubility.) Atoms arrange themselves into two solid phases which are in the shape of lines because this reduces the distance the atoms need to move from the liquid to arrange themselves into the two solid phases.

Question 4

Cooling from the solid phase to another phase?

Answer 4

New solud phase starts to form along the grain boundaries because this is where the diffusion of the solute atoms occurs most easily.

Question 6

Deducing the microstructures at different temperature at different places on the phase diagram.

Answer 6

Go from line to to line. Change in microstructure occurs at every line. If have alpha and liquid going to alpha and beta solid phases