For the Pb-Sn alloy system, (a) What is the compositions and relative amounts of the phases that constitute the eutectic microstructure? (b) For an alloy containing 30% Sn, (i) What are the relative amounts of a and B phases present at the eutectic temperature? (ii) What are the relative amounts of the eutectic and the proeutectic a phase present at the same temperature? Temperature (C) 350 300 250 200 150 100 50 327C a (100% Pb) 18.3 a + L 20 183C Liquid a + 40 wt% Sn 61.9 60 80 232C B+L 97.8 3 100