A 1.5-kg specimen of a 90 wt% Pb–10 wt% Sn alloy is heated to 250°C (480°F); at this tempe...

A 1.5-kg specimen of a 90 wt% Pb–10 wt% Sn alloy is heated to 250°C (480°F); at this temperature it is entirely an α-phase solid solution (Figure 10.8). The alloy is to be melted to the extent that 50% of the specimen is liquid, the remainder being the α 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?

Figure 10.8 The lead–tin phase diagram.