Phase Diagrams Flashcards
What are Phase fields?
Areas on the phase diagrams bordered by phase boundary lines.
What is the liquidus line?
A line in which everything above is in the liquid phase.
What is the solidus line?
A line in which everything below is in solid phases.
What is the Solvus line?
A line that represents a solubility limit
How do we find the mass fraction of liquid and how do we find the mass fraction of solids using the lever rule
- Take a line horizontally across to the phase lines
- Find the length of the line, this is S+L
- Find the length of the line on each side of the point, S and L, S being the line connected to the S phase and L being the line connected to the L phase
- Use the following formulas to find the mass fractions
Mf of L = S/(S+L)
Mf of S = L/(S+L)
What is the terminal solid solution?
Phase region near the extremes of composition, Against a 100% edge
What is the intermediate solid solutions?
Phase regions in the middle of a phase diagram and do not contact a 100% edge.
What are Congruent transformations
Phase change with no change in composition
What are incongruent transformations
Phase change where one or more phases changes composition.
What does Hypoeutectic mean?
Compositions to the left of the eutectic composition.
What does Hypereutectic mean?
Compositions to the right of the eutectic composition.
What does Proeutectic mean?
solids (sometimes grains) which form before the eutectic solidification reaction during cooling of the liquid.
What is Eutectic?
1 phase to 2 phase transition with liquid
What is Eutectoid?
1 phase to 2 phase transition no liquid
What is Peritectic?
2 phases to 1 phase transition with liquid
What is Peritectoid?
2 phases to 1 phase transition no liquid
What is the Gibbs Phase rule?
Gibbs states that the number of phases plus the degrees of freedom must equal the number of components plus 2
Draw a complete solid solubility phase diagram
Liquid on top
Alpha + liquid in middle ellipse
alpha on bottom
Draw a complete solid insolubility phase diagram
Alpha + beta on bottom
liquid on top
Eutectoid in middle
(underline v shape)
Draw a partial solid solubility phase diagram
Liquid on top
alpha to left, beta to right
Alpha +beta bottom middle
eutectoid in the middle
What is a solid solution?
is where impurity atoms have been added, but the crystal structure of the host is retained.
What are the 2 ways a solid solution can happen
Interstitial and substitutional
