1. A 1.5-kg specimen of a 90 wt% Pb-10 wt% Sn alloy is heated to 250 °C (480 F), at which temperature it is entirely an a-phase solid solution (Figure 10.7). The alloy is to be melted to the extent that 50% of the specimen is liquid, the remainder being the a-phase. This may be accomplished either by heating the alloy or changing its composition while holding the temperature constant. a. To what temperature must the specimen be heated? b. How much tin must be added to the 1.5-kg specimen at 250 °C to achieve this state? 300- 327°C 600 Temperature C 100 Liquid 500 L 232°C 183°C 8+2 400 18.3 61.9 978 300 60 80 100 1200 1100 Temperature (°F) PE Composition (Sl 2. A 45 wt% Pb-55 wt% Mg alloy is rapidly quenched to room temperature from an elevated temperature in such a way that the high-temperature microstructure is preserved. This microstructure is found to consist of the a phase and Mg2Pb, having respective weight fractions of 0.65 and 0.35. Determine C, and the temperature from which the alloy was quenched. Tempur 700 600 500 400 300 200 100 0 0 0 20 40 M Composition a+Mg,Pb 60 L 30 40 70 100 11200 MP M 1000 3.- 800 600 A 400 B+ 1200 Mg,Pb 80 100 Temperature (F)

Fig: 1