Metallurgy And Material Science Rr220302

Set No. 1

Code No: RR220302

II B.Tech II Semester Supplimentary Examinations, Apr/May 2007 METALLURGY AND MATERIAL SCIENCE ( Common to Mechanical Engineering, Mechatronics, Production Engineering and Automobile Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Discuss the various types of crystal structures in metals with appropriate examples. [8] (b) What are Miller indices? Explain in detail the procedure for the determination of Miller indices for planes and directions with suitable examples. [8] 2. (a) What do you mean by electron atom ratio in electron compounds. What are the various Electron atom ratios generally observed in electron compounds and what are their corresponding crystal structures. Explain with suitable examples. [10] (b) Explain the general properties of solid solutions.

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3. (a) Draw a neat sketch of F e− F e3 C diagram and label all important points, lines and phases in it. [10] (b) Explain the solidification of hypo eutectic cast Iron.

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4. (a) Explain the effect of alloying elements upon Ferrite and upon carbides/complex carbides. [4x4=16] (b) Explain the term maraging. (c) Give at least four advantages of maraging steels as compared to regular stainless steels. (d) Write a short notes on special purpose tool steels. 5. (a) What is Martensite? Why it is very hard?

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(b) How is hardenability of carbon steel affected by carbon content and grain size? In general how do alloys affect hardenability? [6] (c) What are the principles of good design to obtain best result from heat-treatment. [6] 6. (a) What are the important engineering properties that non-ferrous metals possess, which are not available with ferrous metals? Explain them. [8] (b) Discuss the effect of i. zinc ii. Tin and iii. Nickel on the corrosion resistance of copper. 1 of 2

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Set No. 1

Code No: RR220302 7. Explain the following sintering secondary operations. (a) sizing

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(b) coining

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(c) machining.

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8. (a) Explain the following:

[3x3=9]

i. Reinforcement efficiency ii. Volume ratio iii. Fiber orientations. (b) What do you mean by critical fiber length. Explain the importance of fiber critical length on the behavior of FRP composites. [7] ⋆⋆⋆⋆⋆

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Set No. 2

Code No: RR220302

II B.Tech II Semester Supplimentary Examinations, Apr/May 2007 METALLURGY AND MATERIAL SCIENCE ( Common to Mechanical Engineering, Mechatronics, Production Engineering and Automobile Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Name the different crystal systems and explain their distinguishing characteristics. [8] (b) Copper has FCC structure and it?s atomic radius 1.2780 A. Calculate it’s density (Atomic weight of copper is 63.5). [8] 2. (a) Explain why nickel and copper show continuous solid solubility in each other. [7] (b) Define and explain the following?

[3x3=9]

i. Phase ii. System iii. Polymorphism. 3. (a) Explain the importance and applications of the following:

[3x3=9]

i. Phase rule ii. Lever rule iii. Composition rule. (b) Distinguish between steels and cast irons and highlight the importance of each of them as Engineering Materials. 4. (a) What are the important properties of gray cast Irons? Mention their typical uses. Why gray cast Iron is brittle while malleable iron is not? [6] (b) Distinguish between malleable iron and ductile iron in terms of [2 1/4x4=10] i. ii. iii. iv.

Manufacturing proces Structure Properties and limitations Applications.

5. (a) Compare the diffusion less transformation with diffusion-controlled transformation. [5] (b) Describe the structural transformations taking place in a slowly cooled 0.2 wt% carbon steel. [5] (c) Discuss in brief the stages in tempering process of a steel sample.

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6. (a) Draw the Al-Cu phase diagram upto 10% Cu and explain engineering significance of alloys with 4-5% Cu. [10] 1 of 2

Set No. 2

Code No: RR220302

(b) Explain how Age-hardening improves the mechanical properties of duralumin. [6] 7. (a) Name some unique components which can be manufactured only by powder metallurgy. Describe the manufacture of any two such components in detail. [10] (b) Discuss various types of presses used for die compaction.

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8. (a) What is MMC? Where are they used? Classify the MMCs according to the type of reinforcement. [7] (b) Discuss about the following with relevant examples and applications: i. Continuous- fiber reinforced MMCs. ii. Discontinuous- fiber reinforced MMCs. iii. Particulate reinforced MMCs. ⋆⋆⋆⋆⋆

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[3] [3] [3]

Set No. 3

Code No: RR220302

II B.Tech II Semester Supplimentary Examinations, Apr/May 2007 METALLURGY AND MATERIAL SCIENCE ( Common to Mechanical Engineering, Mechatronics, Production Engineering and Automobile Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Explain with neat sketches the following: i) Edge dislocation ii) Screw dislocation.

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(b) Discuss various types of binding forces that exist in crystalline structures. [8] 2. (a) What is allotrophy? Explain with suitable examples?

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(b) Distinguish between crystal structure microstructure and macrostructure give examples. [10] 3. (a) What is pearlite? Why pearlite is called a micro constituent but not phase? [4] (b) Lead Melts at 3200 C and Tin melts at 2300 C. They form an eutectic containing 62% tin at 1800 C. The maximum solid solubility of Tin in lead at this temperature is 19% of lead in tin is 3%. Assume the solubility of each at room temperature is 1%. i. Draw the phase diagram on a graph paper & label the points, lines and areas in it. ii. Describe the solidification of 40% tin alloy. Sketch the microstructure at room temperature, giving the chemical composition and relative amounts of the phases present. iii. Draw the cooling curve for the above alloy. [12] 4. (a) Explain why is Malleable Iron made from hypo eutectic cast Iron.

[4x4=16]

(b) Is it possible to make modular Iron by heat treatment? Explain. (c) Why should the sulphur content be low in the manufacture of nodular Iron? (d) In the manufacture of Nodular Iron why are inoculants added only just before casting. 5. (a) What are the advantages of specifying steel on the basis of hardenability. [4] (b) Explain any 2 different methods of obtaining a spherodized cementite structure. [6] (c) What are the principle advantages of Austempering compared with the conventional quench and temper method. [6] 6. Discuss the follows; giving composition microstructure, properties and applications, [4x4=16] 1 of 2

Set No. 3

Code No: RR220302 (a) Gunmetal (b) Manganese Bronze (c) Duralumin (d) Muntz metal 7. (a) What is powder Metallurgy?

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(b) When is powder metallurgy preferred over conventional methods.

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(c) What are the advantages and limitations of power metallurgy.

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8. (a) What is delamination? Explain how delamination at the fiber-matrix interface can enhance the fracture toughness of composites. [8] (b) Explain why carbon-reinforced polymer composites find wider applications in aircraft and sports equipment than in automobiles. [8] ⋆⋆⋆⋆⋆

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Set No. 4

Code No: RR220302

II B.Tech II Semester Supplimentary Examinations, Apr/May 2007 METALLURGY AND MATERIAL SCIENCE ( Common to Mechanical Engineering, Mechatronics, Production Engineering and Automobile Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Draw a neat sketch of CPH crystal structure and calculate the theoretical c/a ratio for the above structure. [8] (b) Define the term co-ordination number. What is the significance of co-ordination number? Calculate the Co-ordination number of three cubic space lattices. [8] 2. (a) Distinguish between unsaturated; Saturated and supersaturated solutions with suitable examples. [8] (b) Explain the following with respect to the formation of substitutional solid solutions. i. crystal structure factor ii. Relative size factor.

[4+4]

3. (a) Explain the importance of equilibrium diagrams in the development of new alloys. [6] (b) Bismuth and Antimony are completely soluble in both the liquid and solid states. Bismuth melts at 2900 and Antimony melts at6400 C. An alloy containing 50% Bismuth starts to solidify at 5000 C by separating crystals of 90% Antimony. An alloy containing 80% Bismuth starts to solidify at 4000 C by separating crystals of 75% Antimony. [10] i. Draw the phase diagram to scale on a graph paper labeling all points; lines and phases ii. For an alloy containing Antimony A. give the temperature of inintial solidification B. give the temperature of final solidification C. give the chemical composition and relative amounts of the phases present at 4250 C. D. Draw the cooling curve. 4. (a) Give at least 3 advantages of steels over the family of cast irons.

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(b) What are the various heat treatments given to cast irons? Explain them in brief. [10] 5. Suggest heat treatments explaining the principle: (a) Hardening by carbonitriding 1 of 2

[4x4=16]

Set No. 4

Code No: RR220302 (b) Softening of mild steel wire for redrawing. (c) Improving machinability of 1 % C steel (d) Strengthening of Duralumin alloy.

6. (a) An aircraft manufacturer receives a shipment of aluminium - alloy rivets that are already age hardened. Can they be salvaged? Explain your answer. [8] (b) Write short notes on the following: i. Babbit metals ii. Cupronickels.

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7. (a) What is sintering? What conditions must be satisfied for obtaining a good sintered product? [8] (b) Describe the ingredients and the process used for manufacture of sintered carbide tool tips. [8] 8. (a) What is a hybrid composite? Give important advantages of hybrid composites over normal fiber composites. [8] (b) Why composite materials are considered now a days as structural materials in engineering applications? Reason out. [8] ⋆⋆⋆⋆⋆

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