Rapidly cool to 625°C (1155°F), hold at this temperature for 10 s, rapidly cool to 400°C (750°F), hold at this temperature for 5 s, then quench to room temperature. martensite proeutectoid ferrite bainite fine pearlite austenite i 0 % % % ! de % ! %

Use the Lead-Tin (Pb-Sn) phase diagram below to answer the following questions: Place the following microstructures in the correct order of formation for slowly cooling a 98 wt% Sn alloy from 300 °C to room temperature (point A to point B).

iii) For a 68 wt% Zn-32 wt% Cu alloy, make schematic sketches of the microstructure that would be observed for conditions of very slow cooling at the following temperatures: 1000°C, 760°C, 600°C and 400°C. Label all phases and indicate their approximate compositions. Comportion a In 20 40 60 100 1200 |2200 H2000 Liquid 1000 - 1800 デ+ダ H1600 J400 E 1200 600 400 『+キ 600 200 400 40 60 Conpositon tet% Zro

According to the following graph, two samples of 1080 steel are cooled from the eutectoid temperature, one at a cooling rate of 250°C/s and the other at a cooling rate of 7.27x10-8 °C/s. Specify the phases obtained and explain their formation from thermodynamic and kinetic perspectives. Also, briefly describe their formation. Draw the microstructure of the phases obtained. Sıcaklık (C) 800 700 600 500 400 300 200 100 0 10 1 T M(başlama) M(% 50) M(% 90) 10 M+O -Otektoid Sıcaklık 10² Zaman (s) % 50 10³ 104 105

A 50 wt% Pb-50 wt% Mg alloy is slowly cooled from 700 °C (1290 °F) to 400 °C (750 °F). (a) At what temperature does the first solid phase form? (b) What is the composition of this solid phase? (c) At what temperature does the liquid solidify? (d) What is the composition of this last remaining liquid phase? Temperature (°C) 700 600 500 400 300 200 100 2 0 0 (Mg) 560°C First solid (21 wt% Pb) α 20 465°C 5 a + L Composition (at% Pb) 40 10 L a + Mg₂Pb 20 60 Composition (wt% Pb) Last liquid (67 wt% Pb) 30 Mg₂Pb 40 T T L + Mg₂Pb M 18 80 L + Mg₂Pb 70 100 B B+ Mg₂Pb T B + L D T 1200 1000 800 600 400 200 100 (Pb) Temperature (°F)

rams A copper-nickel alloy of composition 75 wt% Ni-25 wt% Cu is slowly heated from a temperature of 1300°C (1573). (a) At what temperature does the first liquid phase form? (b) What is the composition of this liquid phase? T(°C) 1600 (c) At what temperature does complete melting of the alloy occur? (d) What is the composition of the last solid remaining prior to complete melting? 1500 1400 1300 1200 1100 1000 17 / 17 0 L (liquid) 20 liquidus + a solidus 100% 40 α (FCC solid solution) 60 80 100 wt% Ni 17

Consider the phase diagram below. The three points A, B, and C are at concentrations of 26.4, 31.3, and 34 wt% Ni respectively. The ends of the tie line are at C1 = 25% wt% Ni and C2 = 35 wt% Ni. What are the weight fractions of the alpha phase at A and the L phase at B, as well as the alpha phase/L phase ratio at C? T(°C) 1300 L (liquid) 1200 20 A B C L + a C1 S liquidus L + a solidus a (solid) 50 wt% Ni a. Walpha=0.21; WL=0.33; Walpha/WL = 13.17 b. Walpha=0.09; WL=0.32; Walpha/WL = 15.00 c. Walpha=0.07; WL=0.46; Walpha/WL = 11.17 d. Walpha=0.14; WL=0.37; Walpha/WL = 9.00

Is it possible to have a copper-nickel alloy that, at equilibrium, consists of a liquid phase of composition 20 wt% Ni-80 wt% Cu and also an a phase of composition 37 wt% Ni-63 wt% Cu? If so, what will be the approximate temperature of the alloy? If this is not possible, explain why. Temperature (°C) 1600 1500 1400 1300 1200 1100 1000 0 1085°C (Cu) 20 Liquid Liquidus line L B 40 a+L a A 60 Composition (wt% Ni) (a) 1455°C Solidus line 80 2800 2600 2400 2200 2000 100 (Ni) Temperature (°F) Temperature (°C) 1300 1200 20 Liquid Tie line. a + Liquid a 1 KR I 1 1 B ↑ Co a + Liquid -S 30 CL Composition (wt% Ni) (b) 40 1 Ca a 50

this is material science question

Material science Assuming this system forms a laminar type eutectic, determine the volume proportion of phases for an equilibrium solidified 50% Pb alloy. Sketch the expected microstructure.