Metallurgy And Material Science May2003 Nr 220302

Code No.220302 II-B.Tech. II-Semester Examination April/May, 2003

Set No.

1

METALLURGY AND MATERIAL SCIENCE (common to Mechanical Engineering, Production Engineering, Mechatronics.) Time: 3 hours

Max.Marks:80 Answer any FIVE questions All questions carry equal marks --1. a) Sketch the unit cells of simple Cubie and CPH metals. Calculate the effective number of atoms in each. Give two examples of metal that crystallize in each case. b) Discuss various of binding forces that exist in crystalline structures. 2. 3.

Define the term phase. What are the different types of phases that may exist in a binary phase diagram ? Explain all of them in detail.

Draw tha thermal equilibrium diagram for the following system. Copper, melting point 10830 C. and silver , melting point 9600C, from a eutectic containing 28.5 percent of copper at 7800C. Copper dissolves in solid silver to the extant of 8.8 percent at the eutectic temperature but the maximum solubility limit at 4000C is 1 percent of copper. The maximum solubility limits of silver in copper are 8.0 percent at the eutectic temperature ande 0.95 percent at 4000C. Describe the equilibrium cooling of: a. an alloy containing 6.5 percent copper, b. the eutectic alloy, and c. An alloy containing 40 percent copper. What proportion of the structure of alloy ( c ) will be eutectic mixture? Determine this for a temperature just below the solidus. 4. a) Compute the mass fractions of ∝ ferrite and Cementite in pearlite. b) What is the difference between a phase and a microconstituent? Explain with Examples. 5. a) Describe the structure of grey and white cast irons and account for their continued use as engineering material. b) In what way does the silicon content and section thickness affect the structure of cast iron? c) What are the advantages of nobular iron over malleable iron. 6. a) What are the requirements of an age – hardenable alloy? b) Give a typical heat – treatment schedule for Duralumin and explain the relevant microstructural changes. c) What is seson cracking in brasses ? How can it be removed. 7. a) Differentiate between ceramic and non- ceramic materials. b) How the ceramic materials are classified ? Discuss each class with their characteristics and application. 8. Explain in detail at least four methods of manufacturing of composites with neat sketches. $$$

Code No.220302 II-B.Tech. II-Semester Examination April/May, 2003

Set No.

2

METALLURGY AND MATERIAL SCIENCE (common to Mechanical Engineering, Production Engineering, Mechatronics.) Time: 3 hours

1. a) b) 2. a) b) 3. a) b) 4.

5. a) b) c) 6.

7. a) b) c) 8. a) b) c) d)

Max.Marks:80 Answer any FIVE questions All questions carry equal marks --Derive the relationship between atomic radius and lattice parameter for FCC Materials and calculate it’s packing factor. Define the term solid solution. What are various types of solid solutions? Explain them in detail with neat sketches. Define and explain space lattice, Unit cell and crystal.How are they related. Explain with neat sketches of the following i) Edge Dislocation. ii) Screw Dislocation. What do you understand by the term “ Equilibrium diagram”? Explain with an example. What are the applications of phase diagrams? From the data given below for Bi-Cd system. Plot the equilibrium diagram to scale and find. i) Amount of entectic in 20% cd alloy, and ii) Free cd in 70% cd alloy, given, Melting temperature of Bi = 2710 C Melting temperature of cd = 3210 C Eutectic temperature =1440 C Eutectic composition =39.7% cd. Describe the structure of grey and white cast irons and account for their continued use as engineering material. In what way does the silicon content and section thickness affect the structure of cast iron? What are the advantages of nodular iron over malleable iron. Write short notes on : i) Pack carburizing ii) Nitriding iii) Flame and induction hardening iv) Post-carburiaing heat treatments. What are natural ceramics? Give few examples. Give their composition and uses. What are ceramic composites ? Give few examples. Give their components and their uses Write a note on ceramics for wear applications. Define composite materials. What unique properties have they over the conventional materials? How do the composite materials differ from metallic alloys? Mention some composite materials with their applications. Give their properties. $$$

Code No.220302 II-B.Tech. II-Semester Examination April/May, 2003

Set No.

3

METALLURGY AND MATERIAL SCIENCE (common to Mechanical Engineering, Production Engineering, Mechatronics.) Time: 3 hours

1. a) b) 2. a) b) 3. a) b)

4. a)

b) 5.

6. a) b) c) d) 7. a) b) 8. a) b) c)

Max.Marks:80 Answer any FIVE questions All questions carry equal marks --What are miller indices? Explain in detail the procedure for the determination of Miller indices for planes and directions. Explain briefly about the various types of crystal imperfections, with ehelp of neat sketches. Discuss different types of crystal structures in Metals with appropriate examples. Discuss Hume – Rothery rules for the formation of substitutional solid solutions. Describe with the aid of diagrams: i) Substitutional solid solution ii) Interstitial solid solution. Two hypothetical metals A and B, have melting points of 6000C and 8000C respectively. The two metals are soluble in one another in all proportions in both the liquid and the solid states. Draw the equilibrium diagram for the binary alloy system of metal A and B, and describe the mode of solidification of and alloy of the two metals. The diagram should be nearly drawn and clearly labeled. Explain the importance and applications of i) Phase rule ii) Lever rule iii) Composition Rule. Distinguish between steels and cast Irons, Compound, solid solution and the eutectic alloy. Discuss the following, giving composition, microsturucture, properties and applications. i) Austenitic stainless steels. ii) High speed tool steels. ii) Wear resistant Austenitic steels iv) Si – based die steels. What is the diference between hardness and hardenability? Describe the Jominy and quench test? Discuss the effect of alloying elements of hardenability. What is critical cooling rate? List out the main characteristics of ceramics How the ceramic materials are classified ? Discuss each class with their characteristics and application. Explain the terms: Matrix, Reinforcement and Interface. Write their respective functions. Distinguish between natural composites and man-made composites. Classify the composites according to i) The grometry of the load – bearing components. ii) The materials used i.e., type of reinforcement and type of matrix. $$$$$

Set No.

4

Code No.220302 II-B.Tech. II-Semester Examination April/May, 2003 METALLURGY AND MATERIAL SCIENCE (common to Mechanical Engineering, Production Engineering, Mechatronics.) Time: 3 hours Max.Marks:80 Answer any FIVE questions All questions carry equal marks --1. a) Copper is FCC and has an atomic diameter of 2.5560A .Calculate it’s lattice parameter. b) Differentiate between a crystal, a dendrite, and a grain and gain boundary. c) What is Lattice constant and Co – ordination number? What factors effect the Co – ordination number? Explain them. 2. a) The Lattice constant of Iron is 2.860A. What is the density of iron taking the atomic weight of iron is 55.85 amu. Find the Miller indices of a plane that makes an intercept of 1 on X – axis ,2 on Y – axis and is parallel to Z – axis b) What do you mean by bonds in solids. What are the various types of bonds. Give examples for each of them. 3.

4.

Write short notes on the following: i) The allotropy iron iii) The solidification of pure metals.

ii) iv)

Interstitial solid solutions. Intermetallic compounds.

Define the following structural components: (i) Ferrite (ii) Austenite (iii) Cementite. (iv) pearlite.

5. a) What are the outstanding properties of cupronickel alloys? b) What is season cracking? How may it be minimized? 6. a) What are T – T – T diagrams ? Describe the method for determining the same. b) Discuss the effect of alloying elements on the T – T – T diagram. 7. a) Define a ceramic material. What are some properties common to most ceramic materials? b) Distinguish between traditional and engineering ceramic materials and give examples of each. c) What are the basic steps in the processing of ceramic products by the agglomeration of particles? Explain. 8. a) Write briefly about the ways of occurrence of the cohesion between the matrix and the reinforcement. b) Explain the principle of reinforces composites materials by illustrating the crack propagation with neat sketches. c) What is rule of mixtures? How is it useful in analyzing the strength of the composite? $$$