5.2 | MSE104 - Gibbs Energy Curves

Segment 2 of lecture 5. Relating Gibbs Energy Curves to Phase Diagrams - i.e. the common tangent construction.

Lecturer: Dr David Dye.
Licence: Creative Commons
Department of Materials, Imperial College, London, UK

[sashatupalo]

This is very helpful, informative and clear! Thanks! Worcester Polytechnic Institute student

[ezanadaniel]

you have no idea how much this helped me, thank you so much professor

[wcm]

This was well taught, Thanks a lot! it will really help me during my final. Student from the University of California Irvine!

[ounggilkwon]

Wow thanks you very sooo much.
I'm Korean University Student. Now I studied Phase Diagram, your explanation was a great help me. Thank you ;)

[gomaa]

Your are the best ever seen explaining such a problem. Appreciated

[geoarth_coaching]

Great Lecture Sir!!
I was looking to widen my view on G-X Curves before I could shoot my lecture and your video is very informative. Thank You for the help.
Keep making great content.

[maysamseif]

In a binary eutectic phase diagram with no solid solution at the eutectic temperature, do the alpha and beta curves and the liquid curve all sit on each other at the eutectic composition?

[jonathansnow]

Why are a1 and a2 not considered separate phases with distinct concave upward G(x) functions?

[gokberkdemirok]

Very helpful lecture, thank you. How G vs Xb curve will look like at the temperature where the miscibility gap starts (i.e. at the peak of the miscibility gap curve), thank you.

[flyingbeaver]

I get the graphical representation for the sake of being concise, but how do you calculate the Gibbs free energy of the solid in the liquid region of the phase diagram?

[muhaedalali]

Thank you so much for your lecture, it is really clear and useful

[markmulakazuwa]

great explanation thank you zimbabwe student

[tfs]

What is the next lecture following this one? Very interested in the metastable explanations!

[sairamgoud]

Sir I could not understand how to draw the G-X curve at the eutectic temperature .Could you please explain clearly as their alpha+liq, beta +liq, Alpha+beta, co exist in the equilibrium

[hakanmustafatunc]

Thank you very much! But how do we know the minima's? I mean the slope of a tangent line matters?

[allahbakhsh]

i need a lecture on huron-vidal mixing rule please

[lovelyplanet]

why gibbs free energy curve goes downaward it the start?

[gibbs-]

dG=dH-TdS. so, if we decrease the temperature, I thought that dG of alpha or beta gets increased. why does the dG get lower and lower?

[mathsk]

Did not get why it is the position where the slope of S and L is the same (tangent) and not the direct minimum. Do you know a link for an "algebraic/ physical" explanation.

[burcmm]

In the Eutectic phase diagram, won't the Gibbs energy of the liquid at the last temperature (lowest one where there is alpha, alpha+beta and beta only) be much higher than energies of alpha and beta in the entire range of composition? Or should I see it as the following: A composition that happens to be on the liquid curve (which has lower energy compared to pure alpha or pure beta somewhere at mid composition of B according to the curve you drew), say at 50 weight percent of B, will just form alpha and beta phases according to the common tangent construction. Thank you.