Sample questions from old tests.D01

Sample questions from old tests.D01 - 9. Phase...

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9. Phase Diagrams-basic principles (1) Answer True or False 1. Three phases can coexist over an area in a binary phase diagram. 2. There can be three phases in an alloy in equilibrium over wide range of temperature and composition when it is made up of three components. 3. A phase is made up of different atom kinds and can have different compositions at the same temperature in a given alloy. (2) Fill in the blanks 1. A phase is ________________. (3) Answer questions 1. Give the lever rule and show how it is used. 2. What is the use of lever rule? Explain its principle. 3. In the 60%Cu-40%Ag alloy: a) What phase or phases are present at 1000 ° C? What are their compositions? How much of each phase is present? b) What are the phase or phases present at 600 ° C? What are their compositions? How much of each phase is present? 4. In the Mg-80% Al alloy, (wt%) a) What phase are present at 500 ° C? What are their compositions? b) How much of each phase is present? c) What phase reaction occurs at 451 ° C? Write down the reaction and identify the type. d) What is the composition of the two phase mixture formed? How much two phase mixture is formed? (4) Define: 1. A Eutectic reaction 2. A eutectic 10. Fe-C diagrams/ Introduction to steels and cast irons (1) Answer True or False 1. High carbon content is needed in steels for high strength and wear resistance.(T) 2. The plain carbon steels lose hardness fast during tmpering at 700F.(F) 3. Low carbon steels are used for making springs. (F) 4. (2) Fill in the blanks (3) Answer questions 1. Why are many aluminum alloy excellent casting alloys? 2. How is carbon present in steels? 3. List the following types of cast irons (gray, white, nodular) in order of decreasing ductility. 4. Describe the difference between white and gray cast iron. 5. What is the role of silicon additions to a cost iron composition? 1
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6. How much eutectic is formed in an Fe-3.5%C cast iron as it is cooled from the liquid state? What are the relative proportions of phases in the eutectic? How much cementite will there be at room temperature? 7. How much pearlite is formed in an annealed SAE 1045 steel? How much cementite is contained in it? (Give it with respect to the weight of the alloy). 8. Refer to the Fe-C diagram: a) How much proeutectioid ferrite is formed in SAE 1070 steel when annealed? b) How much eutectoid Fe 3 C(actual amount) is formed in the above steel? c) How much eutectic is formed in 3%C cast iron? d) What is the relative fraction of Fe 3 C in the eutectic? e) What is the composition of the eutectoid in Fe-C alloys? 9. In the SAE 1018 steel, i. How much pearlite is formed? ii. What is the amount of eutectoid? 11. Alloy steels and stainless steels (1) Answer True or False 1. The primary purpose of adding sulphur to steels is to strengthen it at high temperature. 2.
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This note was uploaded on 01/22/2012 for the course ME 2733 taught by Professor Meng during the Fall '10 term at LSU.

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Sample questions from old tests.D01 - 9. Phase...

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