Phase Diagrams\\\\ I. Using the attached phase diagram for the Nickel - Sin syst

Question

Phase Diagrams\

I. Using the attached phase diagram for the Nickel - Sin system identify which of the labelled letters/points correspond to the following reactions upon cooling, and provide the equation governing the reaction/transformation.
a. Eutectic point
b. Eutectoid point
c. Peritectic point
d. Incongruent Melting point
e. Incongruent Transformation point

II. Magnesium alloys are considered the lightest of the structural metals and have consequently gathered considerable attention for aerospace and advanced automotive applications. Additionally, strength gains and further weight reductions can be achieved by alloying with Li metal; forming some of the lightest alloys available. Unfortunately, due to reactive nature of both metals the cost associated with the production and formation of such alloys is generally prohibitive. Using the attached Mg-Li phase diagram, provide the following for an experimental Mg - 7 wt% Li alloy:
a. The phase(s) present of the alloy at 600°C.
b. The liquidus temperature.
c. The fraction of both the liquid and the solid phase at 590°C.
d. The eutectic temperature and composition.
e. Label the phases present in the remaining phase regions (3 total).
f. The maximum solubility of Li in (Mg) and Mg in (Li).

III. The Al2Cu phase is the phase primarily responsible for the majority of the precipitation strengthening which occurs in Al-Cu alloys (2xxx series). Using the following data, calculate the composition of Al2Cu in weight percent Cu (wt% Cu). MAl = 27.0 g/mol and MCu = 63.5 g/mol.

Explanation / Answer

I will answer question III because I don't have solid basics on phases diagram. Post that question in another question thread so you can be answered faster for those questions.

Now for part III, first calculate the molecular weight:

Al2Cu: 2*27 + 63.5 = 117.5 g/mol

Now for the percent:

% = (AW / MW) * 100

%Al = (2*27 / 117.5) * 100 = 45.96%

%Cu = (63.5/117.5) * 100 = 54.04%

Once again, I apologize to not answer the first two questions, but at least I could help you with this question. Please post the first two question per separate in differents post so you can be answered faster and better.

Hope this helps.

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