(Solved): Qu 5 Using the isothermal transformation diagram for an iron-carbon alloy of eutectoid composition ...

Qu 5 Using the isothermal transformation diagram for an iron-carbon alloy of eutectoid composition (Figure 4), specify the nature of the final microstructure (in terms of microconstituents present and approximate percentages of each) of a small specimen that has been subjected to the following timetemperature treatments, In each case assume that the specimen begins at $760^{\circ }\mathrm{C}\left(1400^{\circ }\mathrm{F}\right)$ and that it has been held at this temperature long enough to have achieved a complete and homogeneous austenitic structure. Insert the names of the microstructures leaving one space between them. (a) Rapidly cool to $625^{\circ }\mathrm{C}\left(1160^{\circ }\mathrm{F}\right)$, hold for $10\mathrm{s}$, then quench to room temperature. (b) Rapidly cool to $600^{\circ }\mathrm{C}\left(1110^{\circ }\mathrm{F}\right)$, hold for $4\mathrm{s}$, rapidly cool to $450^{\circ }\mathrm{C}\left(840^{\circ }\mathrm{F}\right)$, hold for $10\mathrm{s}$, then quench to room temperature. Figure 4: Isothermal transformation diagram for an iron-carbon alloy of eutectotd composiion