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  • Topic: Phase transition, Phase changes, Iron
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  • Published : December 15, 2012
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Assignment # 5
Q.1a) On the "blank" phase diagram below, label each of the regions with the phase or phases that are in equilibrium there.

b) How many eutectic points are there in the Cu-P phase diagram? ______ How many eutectoid points? ______ How many peritectics? ______ How many peritectoids? ______ How many pure metal phase transitions? ______ How many congruent melting points??______

Q.2 a) A 90 wt% Ag-10 wt% Cu alloy is heated to a temperature within the b + liquid phase region. If the Composition of the liquid phase is 85 wt% Ag, determine: (a) The temperature of the alloy (b) The composition of the b phase

(c) The mass fractions of both phases b) For a copper-silver alloy of composition 25 wt% Ag-75 wt% Cu and at 775°C (1425°F) do the following: (a) Determine the mass fractions of α and β phases. (b) Determine the mass fractions of primary α and eutectic microconstituents. (c) Determine the mass fraction of eutectic α.

Q.3 For some transformation having kinetics that obeys the Avrami equation. the parameter n is known to have a value of 1.7. If, after 100 s, the reaction is 50% complete, how long (total time)

will it take the transformation to go to 99% completion? The kinetics of the austenite-to-pearlite transformation obeys the Avrami relationship. Using the fraction transformed–time data given below, determine the total time required for 95% of the austenite to transform to pearlite:

Q.4 Write down six invariant Binary reactions by showing schematically and with examples

Due date: 22 October, 2012

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