(20 pts) Using the isothermal transformation diagram for a 0.45 wt% steel alloy, specify the nature of the final microstructure in terms of microconstituents present and approximate percentages) of a small specimen that has been subjected to the following time-temperature treatments. In each case assume that the specimen begins at 850C (1123) and that it has been held at this temperature long enough to have achieved a complete and homogeneous austenitic structure, 900 1600 00 A. A 1400 700 1200 600 o 500 1000 A. A 400 OD SON M 600 X MSON MONI 200 100 100 200 ! 10 10 101 10 a. Cool rapidly to 250C, hold for 103 , then quench to room temperature (3 pts) b. Rapidly cool to 700" hold for 30 then quench to room temperature. (3 pts) Cool rapidly to 398C, hold for 500 s, then quench to room temperature. (3 pes) d. Rapidly cool to 700 C hold at this temperature for 105 s. then quench to room temperature. (3 pts) e. Order these resulting phases in a, b, cand din increasing ductility, Explain your logic (4 pts) Now consider that we performed the same steps from a tod following equilibrium cooling. What would be the resulting microstructure in each case? (4 pts)