Ch9 Flashcards
Phase Diagram
Graphical representation of phases present with respect to given intensive variables under equilibrium
Liquidus
Locus above which everything is liquid
Solidus
Locus below which everything is solid
Tie line
connects the phases in equilibrium with each other (connects between one end to the other end in a particular phase region and parallel to composition axis)
Isomorphous phase diagram
Has 2 phases
Phases
The physically and/or chemically homogeneous material regions present in the phase diagram (e.g., liquid, alpha, and beta [single letters only])
Components
The elements or compounds for which the phase diagrams are plotted
One component
Urnary
Two components
Binary
Three components
Ternary
Three components
Ternary
Intensive Variables
does not dependent on quantity
Intensive Variables
does not dependent on quantity (stuff on x-axis, temperature, pressure, composition)
Extensive Variables
depends on quantity (mass, volume, # of moles)
triple point
where all three phases are in equilibrium (where lines intersect)
How to find weight fraction?
Use Lever Rule
What kind of structure does slow rate of cooling have?
Equilibrium structure
What kind of structure does fast rate of cooling have?
Cored structure
Eutectic phase diagram
T_[alpha] > T_[beta] and Terminal solid solution solidifies at temperatures lower than Alpha and Beta
Peritectic phase diagram)
T_[Alpha] > T_[Beta] and Terminal solid solution solidifies at temperatures higher than B
Solvus
Locus separating different solid phases
Solvus
Locus separating different solid phases
Invariant Reaction
Phase transformations for which degree of freedom is zero
Eutectic Reaction phases?
Liquid to solid + solid (and vice versa)
Degree of Freedom
The number of intensive variables you need for explicitly define everything about a phase or phases present on every point on the phase diagram
Gibb’s Phase Rule
P + F = C + 1
Eutectic (what phases?)
L -> A + B
Eutectiod
Gamma = A + B
Peritectic
L + B = A
