The following data apply to the binary system of A and B: Melting point of pure A = 1050C Melting point of pure B = 1900C At 1250C, the a solid solution (containing 50% of B), the B solid solution (containing 80% of B) and liquid (containing 30% of B) are in three-phase equilibrium. At room temperature, the maximum solubility of B in the a phase is 30% and the maximum solubility of A in the B phase is 10%. (i) Sketch the phase diagram of A and B, showing the phases present in each area of the diagram. (ii) What is the reaction that takes place at 1250C? (iii) What are the weight fractions of the phases present in a material of overall composition 75% B, at 1251C, 1249C and at room temperature (RT)? Answer: (ii) At 1251C, =0.1, fa = 0.9; at 1249C, fa= 0.167, f = 0.833; and %3D at RT, fa = 0.25, fs = 0.75. %3D