Rr220302-metallurgy-and-material-science

Set No. 1

Code No: RR220302

II B.Tech II Semester Supplimentary Examinations, Aug/Sep 2008 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) Derive the relationship between atomic radius and lattice parameter for FCC materials and calculate it’s packing factor. [8] (b) Draw a neat sketch of BCC crystal structure and calculate its packing factor and find out the effective number of atoms. [8] 2. (a) Explain how a cooling curve is determined? What significant information can be obtained from a cooling curve? Explain the significance of a hold, a break and a recovery in a cooling curve. [16] 3. (a) Explain the importance and applications of the following:

[3×3=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. [7] 4. (a) Explain the effect of alloying elements upon Ferrite and upon carbides/complex carbides. [4×4=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 meant by incubation period?

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(b) Why do you obtain a C-shape in the T-T-T diagram?

[4]

(c) What is an athermal transformation?

[4]

(d) Compare the structural features of Pearlite with that of Bainite.

[6]

6. (a) What are the castable types of Aluminium alloys you know? Give the composition and industrial uses of LM6 alloys. [8] (b) Give examples of non-heat treatable type of aluminium alloys. What are their applications. [8] 7. (a) Compare the physical, chemical and mechanical properties of ceramics with those of metals. [9] 1 of 2

Set No. 1

Code No: RR220302 (b) Discuss the different types of bonding in ceramics.

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8. (a) Distinguish between agglomerated materials and laminates, mentioning suitable examples. [6] (b) Explain the importance of particle size in composite materials.

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(c) Explain the differences between matrix and dispersed phase in a composite material. [6] ⋆⋆⋆⋆⋆

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Set No. 2

Code No: RR220302

II B.Tech II Semester Supplimentary Examinations, Aug/Sep 2008 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) Explain the differences between an alloy and alloy system.

[4]

(b) How are the alloy systems classified based on the number of elements present in it. Explain them with suitable examples. [8] (c) Distinguish between homogeneous alloy and heterogeneous alloys. 3. (a) Define and explain the structural phases.

[4] [3×3=9]

i. Ferrite ii. Austenite iii. Cementite. (b) Describe the construction of the phase diagram for 2 metals completely soluble in liquid state and insoluble in solid state. [7] 4. (a) What is the disadvantage of too high a first stage annealing temperature for Malleable Cast Iron? Explain. [8] (b) Why are alloying elements added to steels? Give some examples of common alloying elements and their effect on the properties of steel.. [8] 5. Explain the following: (a) Natural aging

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(b) Artificial aging

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(c) Delayed aging

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(d) Coherent lattice theory

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(e) Solution treatment in Age hardening process.

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6. (a) Name the important properties of Titanium.

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(b) Discuss the properties and applications of Beryllium bronzes.

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(c) Give an account of Red Brasses.

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Set No. 2

Code No: RR220302

7. (a) What is the basic composition of soda-lime glass? Give its advantages, disadvantages and applications. [7] (b) What is the purpose of MgO and Al2 O3 additions to soda-lime glass?

[5]

(c) What is chemically strengthened glass? Why is chemically strengthened glass stronger in tension than annealed glass? [4] 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, Aug/Sep 2008 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) The Maximum solubility of carbon in gamma solid solution is 2% (interstecial void space is 26%) that of alpha Iron is 0.025%). (interstecial void space is 32%). Explain the reasons for the above behavior with neat sketches. [10] (b) Taking only 45 of the most common metals. Calculate maximum the number of possibly binary; ternary and tetranary alloy systems. [6] 3. Silicon and germanium are completely soluble in both liquid and solid states. The melting point of Si is 1700K and the melting point of Ge is 1220 K. For an alloy of 20% Si the freezing range is from 1275K to 1400k. For an alloy of 80% Si, the freezing range is from 1550K to 1650K. [10] (a) Draw the phase diagram and label the areas. (b) Discuss the nature of solidification for 50% silicon alloy.

[6]

4. (a) Explain the Malleabilizing treatment given to white iron castings. Sketch the typical microstructure of malleable cast iron label the phases in it. [8] (b) What is High speed steel? Give the typical composition of High speed steel. Explain the part played by each of the alloying elements in tool steels. Explain the heat treatment process of High speed steel. [8] 5. (a) Explain what is meant by ”Secondary Hardening”.

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(b) What are the alloying elements used to produce this phenomenon in steels?[4] (c) What is meant by age hardening?

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(d) Describe the steps involved in age-hardening process, with the help of an example. [6] 6. (a) How the beta titanium alloys are strengthened.

[4×4=16]

(b) Give at least 2 applications for alpha; alpha-beta and beta titanium alloys. (c) Explain the role of the following elements on the structure and properties of copper alloys. 1 of 2

Set No. 3

Code No: RR220302 i. ii. iii. iv.

lead phosporus aluminium Manganese.

7. (a) Differentiate between ceramic and non-ceramic materials.

[6]

(b) How ceramic components are formed? Explain.

[4]

(c) Compare the properties of crystalline ceramics and glass ceramics.

[6]

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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Set No. 4

Code No: RR220302

II B.Tech II Semester Supplimentary Examinations, Aug/Sep 2008 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) What is stacking sequence? Explain the stacking sequence for FCC and CPH crystal structures with the help of neat sketches. [5] (b) The enthalpy of atomization of diamond is 713 KJ/mole. The listed bond energy is 347 kJ/mole. How do you reconcile the difference. [6] (c) Distinguish between crystal and crystal lattice fully.

[5]

2. (a) What is chemical affinity factor? Should this be high or low for the formation of substitutional solid solutions? Why? [8] (b) Distinguish fully with neat sketches between interstecial solid solutions & interstecial compounds. [8] 3. (a) Define and explain the structural phases.

[3×3=9]

i. Ferrite ii. Austenite iii. Cementite. (b) Describe the construction of the phase diagram for 2 metals completely soluble in liquid state and insoluble in solid state. [7] 4. (a) Explain how the alloying elements that dissolve in Ferrite increase it’s strength. [5] (b) What effect would the addition of 1% Cr have on the properties of a low carbon steel and a high carbon steel? [6] (c) What factors determine the wear resisting properties of steel? 5. (a) What are the requirements of an age-hardenable alloy.

[5] [4]

(b) Give a typical heat treatment schedule for duralumin and explain the relevant microstructural changes. [12] 6. (a) Mention atleast three compositions of copper alloys suitable for the following applications. [2×5=10] i. ii. iii. iv.

Ship propeller Bearings Non-sparking tools Springs 1 of 2

Set No. 4

Code No: RR220302 v. Heat Exchangers.

(b) Discuss briefly the precipitation hardening procedure with specific reference to beryllium copper. [6] 7. (a) List out the main characteristics of ceramics.

[6]

(b) How the ceramic materials are classified? Discuss each class with their characteristics and application. [10] 8. (a) Derive an equation relating the elastic modulus of a layered composite of unidirectional fibers and a plastic matrix, which is loaded under isostrain conditions. [8] (b) Derive an equation relating the elastic modulus of a layered composite of unidirectional fibers and a plastic matrix, which is loaded under isostress conditions. [8] ⋆⋆⋆⋆⋆

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