Gibbs phase diagrams Flashcards
1
Q
When Hmix(s) < 0
A
> Melting is more difficult in alloys
Maximum melting temperature point may appear
Tendency to order at lower temperatures
2
Q
When Hmix(s) > Hmix(l) = 0
A
> Miscibility gap forms
At low temp, free energy curve has negative curvature in middle (concave down)
Minimum melting point temp
Alloys melt at temps below melting temp of their components
3
Q
When Hmix(s)»_space;> 0
A
> Miscibility gap can extend into liquid phase
4
Q
Why does the composition of the equilibrium phase deviate from what the crystal structure predicts?
A
The common tangent doesn’t need include the composition with the minimum free energy
5
Q
Gibbs phase rule
A
F = C - P +2
if pressure is held constant:
F = C - P + 1
