9.51 Consider 2.5 kg of austenite containing 0.65 wt% C, cooled to below 727°C (1341°F). (a) What is the proeutectoid phase? (b) How many kilograms each of total ferrite and cementite form? (c) How many kilograms each of pearlite and the proeutectoid phase form? (d) Schematically sketch and label the resulting microstructure. 1600 1538 °C 8 1400 Composition = 0 wt% Composition = 0 at% Temperature = 0 °C Temperature = 32 °F Composition (at% C) 5 10 15 20 25 1493 °C 1394 °C 7+L 1200 2. Austenite 2.14 1000 800 600 400 912 °C 0.76 0.022 a, Feritte 1085 °C 1 2 L 1147 °C 4.30 a Fe C 3 7+ Fe C 727 °C ' 2500 2000 1500 Cementite (Fe-C) 1000 4 5 6 6.70 Composition (wt% C) Temperature (°F)