(Question 4) (a) The Al-Li phase diagram is shown following figure; 1. Are any intermetallic compounds present? Determine the formula of the compound. (Al, Li are monovalent) 2. Identify the three-phase reactions by writing down the temperature, the reaction in equation form, the composition of each phase in the reaction, and the name of the reaction. (b) Consider an Al-20% Si alloy (in the following figure), Determine; (i) If the alloy is hypoeutectic or hypereutectic; (ii) The composition of the first solid to form during solidification; (iii) The amounts and compositions of each phase at 578°C; (iv) The amounts and compositions of each phase at 576°C; and (v) The amounts and compositions of each phase for the eutectic composition at 500°C. 11-24 3+ 1125 - Der 11-25 4 . NO (Question 3) a. Consider 10 kg of austenite containing 0.65 wt% C and cooled to below 727°C. (i) What is the proeutectoid phase? (ii) How many kilograms each of total ferrite and cementite form? (iii) How many kilograms each of pearlite and the proeutectoid phase form? (iv) Schematically sketch and label the resulting microstructure. (v) Write the compete equations for the three reactions in following Fe-C diagram, what is the name of each 1600 reaction. 1530 C Compton C -14 1400 13 +2 1200 3000 912 800 600 400 0.76 0.022 1147C 2.34 4.30 Composition C 72716 Cemen b. The following figure shows stress-strain curves for three failed tensile-test specimens. All are plotted on the same scale. 1. Characterize each material as brittle or ductile. 2. Which is the stiffest? 3. Which has the highest ultimate strength? 4. Which has the largest modulus of resilience? 5. Which has the largest modulus of toughness? Stress Stress Stress (a) Strain Strain € Strain