a)(i) What is the melting point of pure Mg? (ii) What is the maximum solubility of Mg in Pb and at what temperature does this occur? (b) A 50 wt.% Pb-50wt% Mg alloy is slowly cooled from 700 °C to 400 °C. (i) At what temperature does the first solid phase form? (ii) What is the composition of this solid phase? (iii) At what temperature does all the liquid solidify? (iv) What is the composition of the last remaining liquid phase? (v) What is the freezing range? (c) What is the mass fraction of solid and liquid of a 60 wt.% Mg alloy at a temperature of 500 °C.
BINARY PHASE DIAGRAMS
Please answer ALL parts with as much explanation as possible, showing full working out.
a)(i) What is the melting point of pure Mg?
(ii) What is the maximum solubility of Mg in Pb and at what temperature
does this occur?
(b) A 50 wt.% Pb-50wt% Mg alloy is slowly cooled from 700 °C to 400 °C.
(i) At what temperature does the first solid phase form?
(ii) What is the composition of this solid phase?
(iii) At what temperature does all the liquid solidify?
(iv) What is the composition of the last remaining liquid phase?
(v) What is the freezing range? (c) What is the mass fraction of solid and liquid of a 60 wt.% Mg alloy at a
temperature of 500 °C.
(d) Draw and label the microstructure of an 80 wt.% Mg alloy at 600 °C.
(e) A Mg-Pb alloy of mass 5.5 kg has a composition just slightly below the
solubility limit of 200 °C.
(i) What mass of lead is in the alloy?
(ii) If the alloy is heated to 350 °C how much more lead can be dissolved
in the α phase without exceeding the solubility limit of this phase?
Trending now
This is a popular solution!
Step by step
Solved in 7 steps with 6 images
