If you want to see how eutectic diagrams are created click here
The first and most noticable point on this diagram is the Eutectic point. The eutectic point as can be seen above is a point in the diagram where the liquid alloy changes to a solid without going through a pasty state. This is the lowest melting point of any composition for the alloy.
The Diagram below will aid you in your understanding of what happens in the different zones in the eutectic thermal diagram.
As you would except everything above the liquidus line is in the
liquid state and in this state the two metals are totally soluble in each
other.
In the eutectic point region (represented by the green line)
there is only the eutectic composition alloy .
If you look at 100% Cadmium you will see that there is a large amount
of solid Cadmium while this decreases in the alloys found nearer to the
eutectic. The same applies for Bismuth. Therefore we can say that as the
composition of the alloy moves away from the eutectic composition, grains
of either Cadmium or Bismuth appear in the eutectic matrix.
You are now ready to move on to the next tpye of alloy combination i.e Partial solubility.
