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2. Phase Diagrams [25 Points] a. Unary phase diagrams involve one/three components (pick one) [1 point]. Lever rule helps us calculate fractions of phases [1 point]. b. A 50 wt% Ni-50 wt% Cu alloy is slowly cooled from 1400°C (2550°F) to 1200°C (2190°F). [3 points, 1 each for (1), (2) and (3)] (1) At what temperature does the first solid phase form? (2) What is the composition of this solid phase? (3) At what temperature does the liquid solidify? at % Ni 20 80 100 1500 1455 °C 1400 1300 1200 1100 1000 Temperature (°C) 1 I 1085 °C 0 (Cu) 20 Liquid 40 Liquidus "a+L Solidus 60 Solid (a) 60 40 wt.% Ni 80 100 (Ni)
c. Using the Pb-Sn phase diagram, indicate the phases that are present and the approximate compositions of the phases. Also, determine the relative amounts (in terms of mass fractions) of the phases for the alloys and temperatures. [10 points, 5 each for (1) and (2)] (1) 76 wt% Pb-24 wt% Sn at 250°C (2) 70 wt% Sn-30 wt% Pb at 300°C Composition (at'% Sn) 0 40 60 100 Temperature (C) 300 200 100 327°C (PM W.L 16.3 20 Liquid 183 C 40 60 Composition (wt% ) 61.9 80 PL 232C 97.8 100 (54) 600 500 400 300 200 100 Temperature (°F)
d. For the Iron - Iron Carbide (Fe-Fe3C) phase diagram, compare and contrast hypoeutectoid and hypereutectoid alloys. What is the eutectoid temperature in this phase diagram? Draw a schematic of the microstructure for both hypoeutectoid and hypereutectoid alloys. How does the carbon content vary for these alloys? [10 points] (This question is for 10 points. Please answer in full sentences and provide details and draw schematics clearly pointing out microstructural components, features etc.) Composition (at C) 1600 15380 -1493 C 2500 2000 Temperature C 1400 1200 1000 800 600 400 1394℃ 7. Au $12€ Fas 0.76 0.022 a Ferde Y+L 10 2.14 1147 C · Tex 4 Comp%C 14.30 rajo 727/0 Cement. 1900 1000 670 Temperatus FF