Fig. 9.23 represents the magnesium-silicon thermal equilibrium diagram, (i) Given that X is a...
Fig. 9.23 represents the magnesium-silicon thermal equilibrium diagram,
(i) Given that X is a chemical compound derive its formula. (Atomic masses: Mg-24.3; Si-28.1);
(ii) Annotate the diagram completely;
(iii) What phases can co-exist at E?
(iv) What will happen if the temperature of the alloy represented by E is raised by a small amount?
(v) What are the compositions of the phasespresent in an alloy containing 80% Si-20% Mg overall, at a temperature of 11000C?
(vi) In what proportions by mass will the phases in (v) be present?
(vii) Describe, step by step, what happens as an alloy containing 50% of each element cools slowly from 12000C to 7000C;
(viii) What will be the compositions of the phases present at 7000C?
(ix) In what proportions will the phases in (viii) be present?
