CME 261 Homework Questions Chapter 9 Phase diagrams Spring 2021 PDF

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CME 261 Homework Questions Chapter 9 Phase diagrams Spring 2021...

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CME/ME 261 Homework Questions

Chapter 9

Phase diagrams

1. Refer to the Cu-Ni Phase Diagram (Figure 2) to answer the following: A 65 wt% Ni–35 wt% Cu alloy is heated to a temperature within the α + liquid-phase region. If the composition of the α phase is 70 wt% Ni, determine: (a) The temperature of the alloy (b) The composition of the liquid phase (c) The mass fractions of both phases

2. Refer to the Pb-Sn Phase Diagram Figure 5) to answer the following: A lead–tin alloy of composition 30 wt% Sn–70 wt% Pb is slowly heated from a temperature of 150°C (300°F). (a) At what temperature does the first liquid phase form? (b) What is the composition of this liquid phase? (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?

3. Refer to the Pb-Sn Phase Diagram (Figure 5) to answer the following: For 2.8 kg of a lead–tin alloy, is it possible to have the masses of primary (ie. Proeutectic) β and total β of 2.21 and 2.53 kg, respectively, at 180°C (355°F)? Why or why not?

4. Refer to the Al-Si phase diagram(Figure 11) to answer the following: If an Al10weight% Si alloy is cooled from 700oC, a) At what temperature does the first solid form? b) What is the composition of that solid? c) What fraction of the final solidified metal will have the eutectic structure?

5. Refer to the diagram below to answer the following: This is the tin–gold phase diagram, for which only single-phase regions are labeled. Specify temperature–composition points at which all eutectics, eutectoids, peritectics, and congruent phase transformations occur. Also, for each, write the reaction upon cooling. If there is a congruent melting phase on the diagram, identify it and give its melting point....