2018 021305

B.Tech. 3rd Semester Examination, 2018

Time 03 Hours
Full Marks 70
Instructions:
  • There are Nine Questions in this Paper.
  • Attempt Five questions in all.
  • Question No. 1 is Compulsory.
  • The marks are indicated in the right hand margin.

  1. Choose the correct answer (any seven):

Q1.a

The atomic packing factor is the highest in which of the following cubic lattice system?

a)

Simple Cubic

b)

Body Centered Cubic (BCC)

c)

Face Centered Cubic (FCC)

d)

Diamond Cubic

Q1.b

Raw material for all iron and steel product is ________.

a)

Cast iron

b)

Wrought iron

c)

Pig iron

d)

Steel

Q1.c

Grey cast iron has ________.

a)

brittleness

b)

low electrical conductivity

c)

low compressive strength

d)

All options are correct

Q1.d

18-4-1 high speed steel contains:

a)

18% carbon

b)

4% carbon

c)

1% carbon

d)

0.7% carbon

Q1.e

Essential gradient of any hardened steel is ________.

a)

Carbon

b)

Cementite

c)

Martensite

d)

Pearlite

Q1.f

Thermodynamically stable defects

a)

Point defects

b)

Line defects

c)

Surface defects

d)

Volume defects

Q1.g

Beneficial property of foreign particles

a)

Reduces density

b)

Act as stress raisers

c)

Obstructs dislocation motion

d)

None

Q1.h

Time dependent recoverable deformation under load is called

a)

Elastic deformation.

b)

Anelastic deformation

c)

Elastic after effect

d)

Visco-elastic deformation

Q1.i

Decrease in free energy during recrystallization is attributed to

a)

Excess point defects

b)

Excess dislocations

c)

Grain boundaries

d)

All

Q1.j

Phase formed of diffusion-less reaction:

a)

Pearlite

b)

Lower Bainite

c)

Upper bainite

d)

Martensite

Section B

Q2

Solve the following:

Q3

Solve the following:

Q4

Solve the following:

Q5

Solve the following:

Q6

Solve the following:

Q7

Solve the following:

Q8

Identify and draw all slip systems associated with FCC crystal. Calculate the tensile stress that is applied along the [12ˉ0][1 \bar{2} 0] axis of a gold crystal to cause slip on the (11ˉ1ˉ)[01ˉ1](1 \bar{1} \bar{1}) [0 \bar{1} 1] slip system, if the critical resolved shear stress is 10 MPa.

Q9

Write short notes on the following:


2017 021305

B.Tech. 3rd Semester Examination, 2017

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct answer (any seven):

Q1.1

Which of the following is strong and ductile materials?

a)

Polymers

b)

Ceramics

c)

Metals

d)

Semiconductors

Q1.2

Which of the following statements is false?

a)

Line defects are thermodynamically stable

b)

Dislocation can end inside a crystal without forming loop

c)

ABC ABC ABC is stacking sequence for HCP crystal

d)

All of the above

Q1.3

Time-dependent permanent deformation is called

a)

plastic deformation

b)

elastic deformation

c)

creep

d)

Anelastic deformation

Q1.4

The most factor influencing diffusivity is

a)

diffusing species

b)

temperature

c)

lattice structure

d)

presence of defects

Q1.5

Which of the following is not a Hume-Ruthery condition?

a)

Crystal structure of each element of solid solution must be the same

b)

Size of atoms of each two elements must not differ by more than 15%

c)

Elements should form compounds with each other

d)

Elements should have the same valence

Q1.6

Phase formed of diffusionless reaction is

a)

pearlite

b)

lower bainite

c)

upper bainite

d)

martensite

Q1.7

Eutectoid product in Fe-C system is called

a)

pearlite

b)

bainite

c)

ledeburite

d)

spheroidite

Q1.8

Failure due to excessive deformation is controlled by

a)

material properties

b)

design and dimensions

c)

Both (i) and (ii)

d)

None of the above

Q1.9

Most often machine components are failed by

a)

buckling

b)

creep

c)

fatigue

d)

All of the above

Q1.10

Last constituent to fail in fiber reinforced composites is

a)

matrix

b)

fiber

c)

Both fails at same time

d)

Can't define

Q.2 Solve both questions :

Q2.1

The accompanying figure shows the atomic packing schemes for several different crystallographic directions for a hypothetical metal. For each direction, the circles represent only the atoms contained within a unit cell, the circles are reduced from their actual size. Draw the unit cell and identify the crystal structure.

Question Diagram
Q2.2

Show that a line of dislocation contains edge, screw or mixed dislocations.

Q.3 Solve both questions :

Q3.1

For aluminium (atomic radius 0.1431 nm), compute the inter-planer spacing for (110) set of planes.

Q3.2

Calculate the atomic packing fraction for diamond cubic crystal and find its density (atomic radius $ r = 0.77 \text{ \AA} $).

Q.4 Solve this question :

Q4.1

Construct and label different regions of Ag-Cu phase diagram using the following data: Melting point of $ \text{Ag} = 960^\circ\text{C} $, Melting point of $ \text{Cu} = 1085^\circ\text{C} $, At eutectic point $ = 780^\circ\text{C} $, eutectic composition = 28 wt% Cu, maximum solubility of Ag in $ \text{Cu} = 8 \text{ wt%} $, maximum solubility of Cu in $ \text{Ag} = 6 \text{ wt%} $. At room temperature, maximum solubility of Ag in $ \text{Cu} = 3 \text{ wt%} $ and maximum solubility of Cu in $ \text{Ag} = 2 \text{ wt%} $. Assume the liquids, solidus and solvus line are straight. Calculate the amount of proeutectic phase in 60 wt% Cu alloy at $ 779^\circ\text{C} $ and draw the change in micro-structures when cooled slowly from liquid state to room temperature.

Q.5 Solve this question :

Q5.1

Construct isothermal transformation diagram for eutectoid steel, determine and draw the final microstructure of a small specimen that has been subjected to the following time-temperature treatment. In each case, assume that the specimen begins at $ 800^\circ\text{C} $, and that it has been held at this temperature long enough to have achieved a complete and homogeneous austenite structure:
(a) Rapidly cool to $ 250^\circ\text{C} $, hold for $ 10^5\text{ s} $, then quench to room temperature
(b) Rapidly cool to $ 400^\circ\text{C} $, hold for 10 s, then quench to room temperature
(c) Rapidly cool to $ 700^\circ\text{C} $, hold for $ 10^5\text{ s} $ then quench to room temperature
(d) Rapidly cool to $ 650^\circ\text{C} $ hold at this temperature for 6 s, rapidly cool to $ 400^\circ\text{C} $, hold for 10 s, then quench to room temperature

Q.6 Solve this question:

Q6.1

For a polymer-matrix fiber-reinforced composite-

list three functions of the matrix phase;

compare the desired mechanical characteristics of matrix and fiber phases;

cite two reasons why there must be a strong bond between fiber and matrix at their interface.

Q.7 Solve this question:

Q7.1

A continuous and aligned glass fiber-reinforced composite consists of 30 vol% of glass fibers having a modulus of elasticity of 69 GPa and 70 vol% of a polyester resin that, when hardened, displays a modulus of 3.4 GPa.

Compute the modulus of elasticity of this composite in the longitudinal direction.

If the cross-sectional area is $ 250 \text{ mm}^2 $ and a stress of 40 MPa is applied in this longitudinal direction, compute the magnitude of the load carried by each of the fiber and matrix phases.

Determine the strain that is sustained by each phase when the stress in part (b) is applied.

Q.8 Solve both questions :

Q8.1

What is cast iron? How does it differ from pig iron?

Q8.2

Compare ductile (nodular) cast iron with other cast iron on the basis of mechanical properties, composition and microstructure.

Q.9 Write short notes on the following:

Q9.1

(a) Composite and alloys

Q9.2

(b) Annealing and normalizing

Q9.3

(c) Cross-slip and jog

Q9.4

(d) Frank-Read source


2017 V4 021305

B.Tech. 3rd Semester Examination, 2017

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct answer (any seven):

Q1.1

Which of the following is strong and ductile materials?

a)

Polymers

b)

Ceramics

c)

Metals

d)

Semiconductors

Q1.2

Which of the following statements is false?

a)

Line defects are thermodynamically stable

b)

Dislocation can end inside a crystal without forming loop

c)

ABC ABC ABC is stacking sequence for HCP crystal

d)

All of the above

Q1.3

Time-dependent permanent deformation is called

a)

plastic deformation

b)

elastic deformation

c)

creep

d)

Anelastic deformation

Q1.4

The most factor influencing diffusivity is

a)

diffusing species

b)

temperature

c)

lattice structure

d)

presence of defects

Q1.5

Which of the following is not a Hume-Ruthery condition?

a)

Crystal structure of each element of solid solution must be the same

b)

Size of atoms of each two elements must not differ by more than 15%

c)

Elements should form compounds with each other

d)

Elements should have the same valence

Q1.6

Phase formed of diffusionless reaction is

a)

pearlite

b)

lower bainite

c)

upper bainite

d)

martensite

Q1.7

Eutectoid product in Fe-C system is called

a)

pearlite

b)

bainite

c)

ledeburite

d)

spheroidite

Q1.8

Failure due to excessive deformation is controlled by

a)

material properties

b)

design and dimensions

c)

Both (i) and (ii)

d)

None of the above

Q1.9

Most often machine components are failed by

a)

buckling

b)

creep

c)

fatigue

d)

All of the above

Q1.10

Last constituent to fail in fiber reinforced composites is

a)

matrix

b)

fiber

c)

Both fails at same time

d)

Can't define

Q.2 Solve both questions :

Q2.1

The accompanying figure shows the atomic packing schemes for several different crystallographic directions for a hypothetical metal. For each direction, the circles represent only the atoms contained within a unit cell, the circles are reduced from their actual size. Draw the unit cell and identify the crystal structure.

Question Diagram
Q2.2

Show that a line of dislocation contains edge, screw or mixed dislocations.

Q.3 Solve both questions :

Q3.1

For aluminium (atomic radius 0.1431 nm), compute the inter-planer spacing for (110) set of planes.

Q3.2

Calculate the atomic packing fraction for diamond cubic crystal and find its density (atomic radius $ r = 0.77 \text{ \AA} $).

Q.4 Solve this question :

Q4.1

Construct and label different regions of Ag-Cu phase diagram using the following data: Melting point of $ \text{Ag} = 960^\circ\text{C} $, Melting point of $ \text{Cu} = 1085^\circ\text{C} $, At eutectic point $ = 780^\circ\text{C} $, eutectic composition = 28 wt% Cu, maximum solubility of Ag in $ \text{Cu} = 8 \text{ wt%} $, maximum solubility of Cu in $ \text{Ag} = 6 \text{ wt%} $. At room temperature, maximum solubility of Ag in $ \text{Cu} = 3 \text{ wt%} $ and maximum solubility of Cu in $ \text{Ag} = 2 \text{ wt%} $. Assume the liquids, solidus and solvus line are straight. Calculate the amount of proeutectic phase in 60 wt% Cu alloy at $ 779^\circ\text{C} $ and draw the change in micro-structures when cooled slowly from liquid state to room temperature.

Q.5 Solve this question :

Q5.1

Construct isothermal transformation diagram for eutectoid steel, determine and draw the final microstructure of a small specimen that has been subjected to the following time-temperature treatment. In each case, assume that the specimen begins at $ 800^\circ\text{C} $, and that it has been held at this temperature long enough to have achieved a complete and homogeneous austenite structure:
(a) Rapidly cool to $ 250^\circ\text{C} $, hold for $ 10^5\text{ s} $, then quench to room temperature
(b) Rapidly cool to $ 400^\circ\text{C} $, hold for 10 s, then quench to room temperature
(c) Rapidly cool to $ 700^\circ\text{C} $, hold for $ 10^5\text{ s} $ then quench to room temperature
(d) Rapidly cool to $ 650^\circ\text{C} $ hold at this temperature for 6 s, rapidly cool to $ 400^\circ\text{C} $, hold for 10 s, then quench to room temperature

Q.6 Solve this question:

Q6.1

For a polymer-matrix fiber-reinforced composite-

list three functions of the matrix phase;

compare the desired mechanical characteristics of matrix and fiber phases;

cite two reasons why there must be a strong bond between fiber and matrix at their interface.

Q.7 Solve this question:

Q7.1

A continuous and aligned glass fiber-reinforced composite consists of 30 vol% of glass fibers having a modulus of elasticity of 69 GPa and 70 vol% of a polyester resin that, when hardened, displays a modulus of 3.4 GPa.

Compute the modulus of elasticity of this composite in the longitudinal direction.

If the cross-sectional area is $ 250 \text{ mm}^2 $ and a stress of 40 MPa is applied in this longitudinal direction, compute the magnitude of the load carried by each of the fiber and matrix phases.

Determine the strain that is sustained by each phase when the stress in part (b) is applied.

Q.8 Solve both questions :

Q8.1

What is cast iron? How does it differ from pig iron?

Q8.2

Compare ductile (nodular) cast iron with other cast iron on the basis of mechanical properties, composition and microstructure.

Q.9 Write short notes on the following:

Q9.1

(a) Composite and alloys

Q9.2

(b) Annealing and normalizing

Q9.3

(c) Cross-slip and jog

Q9.4

(d) Frank-Read source


2015 021305

B.Tech. 3rd Semester Examination, 2015

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct answer (any seven):

Q1.1

Which of the following materials is the hardest?

a)

Alumina

b)

High-carbon steel

c)

Cast iron

d)

Diamond

Q1.2

The phase boundary between $ \alpha $ and $ (\alpha + \beta) $ regions is called

a)

liquidus

b)

solidus

c)

solvus

d)

eutectic

Q1.3

The interstitial solid solution of carbon in $ \gamma $-iron is called

a)

cementite

b)

ferrite

c)

austentite

d)

pearlite

Q1.4

For a spherical particle of radius r, the volume to surface area ratio is

a)

r3\frac{r}{3}

b)

3r3r

c)

πr3\frac{\pi r}{3}

d)

None of these

Q1.5

Which of the following refers to eutectoid reaction?

a)

Lα+βL \rightarrow \alpha + \beta

b)

αβ+γ\alpha \rightarrow \beta + \gamma

c)

α+Lβ\alpha + L \rightarrow \beta

d)

α+βγ\alpha + \beta \rightarrow \gamma

Q1.6

If one solid phase splits into two solid phases on heating, the reaction is

a)

eutectoid

b)

peritectoid

c)

eutectic

d)

peritectic

Q1.7

Cast iron normally contains

a)

1 to 1.5% C

b)

2 to 4% C

c)

less than 1% C

d)

None of the above

Q1.8

Piezo-electric materials produce electric field when subjected to

a)

magnetic field

b)

optical rays

c)

thermal radiation

d)

mechanical force

Q1.9

Examples of ferrous metals are

a)

copper, brass, nickel

b)

aluminium, titanium, zinc

c)

cast iron, steel, alloy steel

d)

alumina, zirconia, silica

Q1.10

In a single-component system, the maximum no. of phases that can co-exist in equilibrium, is

a)

2

b)

3

c)

4

d)

5

Q.2 Solve these questions:

Q2.1

State and explain the equation for Gibbs phase rule.

Q2.2

Derive the lever rule for the amount in wt. percent of each phase in two phase regions of a binary phase diagram.

Q.3 Solve these questions:

Q3.1

What is a hybrid composite?

Q3.2

Write the important advantages of hybrid composites over normal fiber composites.

Q3.3

Find an expression for the modulus of elasticity for a hybrid composite in which all fibers of both types are oriented in the same direction.

Q.4 Solve both questions :

Q4.1

Explain with reason why glass fiber reinforced composites are utilized extensively.

Q4.2

Explain the limitations of glass fiber reinforced composites.

Q.5 Solve this question:

Q5.1

Compare gray and malleable cast iron with respect to:

(a) composition and heat treatment;

(b) microstructure;

(c) mechanical characteristics.

Q.6 Solve these questions:

Q6.1

What is the distinction between cement and concrete?

Q6.2

Write some important limitations that restrict the use of concrete as structural material.

Q6.3

Explain the techniques that are utilized to strengthen concrete by reinforcement.

Q.7 Solve both questions :

Q7.1

Classify different types of materials with their properties and application.

Q7.2

Write short notes on the following: (i) Biomaterial (ii) Optical fiber (iii) Nanomaterials

Q.8 Solve these questions:

Q8.1

Draw the lead-tin phase diagram.

Q8.2

What are the compositions of phases?

Q8.3

Calculate the relative amount of each phase present in terms of mass fraction.

Q.9 Write notes on the following:

Q9.1

(a) Bainite

Q9.2

(b) White cast iron

Q9.3

(c) Martensite

Q9.4

(d) Hume-Rothery Rules


2015 V4 021305

B.Tech. 3rd Semester Examination, 2015

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct answer (any seven):

Q1.1

Which of the following materials is the hardest?

a)

Alumina

b)

High-carbon steel

c)

Cast iron

d)

Diamond

Q1.2

The phase boundary between $ \alpha $ and $ (\alpha + \beta) $ regions is called

a)

liquidus

b)

solidus

c)

solvus

d)

eutectic

Q1.3

The interstitial solid solution of carbon in $ \gamma $-iron is called

a)

cementite

b)

ferrite

c)

austentite

d)

pearlite

Q1.4

For a spherical particle of radius r, the volume to surface area ratio is

a)

r3\frac{r}{3}

b)

3r3r

c)

πr3\frac{\pi r}{3}

d)

None of these

Q1.5

Which of the following refers to eutectoid reaction?

a)

Lα+βL \rightarrow \alpha + \beta

b)

αβ+γ\alpha \rightarrow \beta + \gamma

c)

α+Lβ\alpha + L \rightarrow \beta

d)

α+βγ\alpha + \beta \rightarrow \gamma

Q1.6

If one solid phase splits into two solid phases on heating, the reaction is

a)

eutectoid

b)

peritectoid

c)

eutectic

d)

peritectic

Q1.7

Cast iron normally contains

a)

1 to 1.5% C

b)

2 to 4% C

c)

less than 1% C

d)

None of the above

Q1.8

Piezo-electric materials produce electric field when subjected to

a)

magnetic field

b)

optical rays

c)

thermal radiation

d)

mechanical force

Q1.9

Examples of ferrous metals are

a)

copper, brass, nickel

b)

aluminium, titanium, zinc

c)

cast iron, steel, alloy steel

d)

alumina, zirconia, silica

Q1.10

In a single-component system, the maximum no. of phases that can co-exist in equilibrium, is

a)

2

b)

3

c)

4

d)

5

Q.2 Solve these questions:

Q2.1

State and explain the equation for Gibbs phase rule.

Q2.2

Derive the lever rule for the amount in wt. percent of each phase in two phase regions of a binary phase diagram.

Q.3 Solve these questions:

Q3.1

What is a hybrid composite?

Q3.2

Write the important advantages of hybrid composites over normal fiber composites.

Q3.3

Find an expression for the modulus of elasticity for a hybrid composite in which all fibers of both types are oriented in the same direction.

Q.4 Solve both questions :

Q4.1

Explain with reason why glass fiber reinforced composites are utilized extensively.

Q4.2

Explain the limitations of glass fiber reinforced composites.

Q.5 Solve this question:

Q5.1

Compare gray and malleable cast iron with respect to:

(a) composition and heat treatment;

(b) microstructure;

(c) mechanical characteristics.

Q.6 Solve these questions:

Q6.1

What is the distinction between cement and concrete?

Q6.2

Write some important limitations that restrict the use of concrete as structural material.

Q6.3

Explain the techniques that are utilized to strengthen concrete by reinforcement.

Q.7 Solve both questions :

Q7.1

Classify different types of materials with their properties and application.

Q7.2

Write short notes on the following: (i) Biomaterial (ii) Optical fiber (iii) Nanomaterials

Q.8 Solve these questions:

Q8.1

Draw the lead-tin phase diagram.

Q8.2

What are the compositions of phases?

Q8.3

Calculate the relative amount of each phase present in terms of mass fraction.

Q.9 Write notes on the following:

Q9.1

(a) Bainite

Q9.2

(b) White cast iron

Q9.3

(c) Martensite

Q9.4

(d) Hume-Rothery Rules


2013 021305

B.Tech. 3rd Semester Examination, 2013

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct answer (any seven):

Q1.1

Which is closest to the purest form of iron?

a)

Cast iron

b)

Wrought iron

c)

Grey iron

d)

Mild steel

Q1.2

The process of isothermal transformation to form bainite in steel, is known as

a)

austempering

b)

austeniting

c)

barkerising

d)

polymerization

Q1.3

Which of the following is not a permanent magnetic material?

a)

Chromium steel

b)

Silicon iron

c)

Cobalt steel

d)

Alnico

Q1.4

Which one of the following materials is viscoelastic in nature?

a)

Nylon

b)

Glass

c)

Rubber

d)

Graphite

Q1.5

If the structure of a sample consists of pearlite, cementite and free carbon, the sample may be

a)

cast iron

b)

alloy steel

c)

dead mild steel

d)

eutectoid steel

Q1.6

Pearlite is obtained when steel is

a)

quenched in oil

b)

cooled in still air

c)

slowly cooled in furnace

d)

quenched in water

Q1.7

A material having different properties in different directions, is known as

a)

isotropic

b)

amorphous

c)

austenitic

d)

anisotropic

Q1.8

Temperating of hardened steel is done to increase its

a)

ductility

b)

grain size

c)

surface condition

d)

carbon content

Q1.9

The fatigue strength of materials increases

a)

with temperature

b)

by providing scratches on the surface

c)

by providing notches

d)

by under-stressing the material

Q1.10

The capacity of a metal to exhibit considerable elastic recovery upon release, is known as

a)

toughness

b)

resilience

c)

hardness

d)

stiffness

Q.2 Solve both questions :

Q2.1

Give the classification of ceramic materials, organic materials, electrical materials and magnetic materials with their properties and applications.

Q2.2

Write short notes on: (i) Nanomaterials (ii) Biomaterials (iii) Optical fibre

Q.3 Solve these questions:

Q3.1

What is a 'phase diagram'? How is it classified? What useful information does it provide?

Q3.2

State Gibbs' phase rule. What is the minimum and maximum number of phases which could exist in a pure metal?

Q3.3

Discuss the Hume-Rothery rules for alloy formation.

Q.4 Solve this question :

Q4.1

Draw the iron-carbon phase diagram and discuss briefly the structure and properties of steel having 0.83% and 0.40% carbon when cooled from $ 1000^\circ\text{C} $ to room temperature.

Q.5 Solve both questions :

Q5.1

Draw a TTT diagram of eutectoid steel. Discuss all the transformation with the rate of cooling.

Q5.2

Why continuous cooling of plain carbon steel does not show bainite in its microstructure?

Q.6 Solve these questions:

Q6.1

What effect does a change in heating or cooling rate have upon the transformation temperature in steel?

Q6.2

Calculate the thickness of micro-constituents present in pearlite if density of ferrite and cementite is $ 7.76 \text{ gm/cc} $ and $ 7.66 \text{ gm/cc} $ respectively.

Q6.3

A steel contains 40% ferrite and 60% pearlite at room temperature. Determine the amount of total ferrite and cementite present in the alloy.

Q.7 Solve both questions :

Q7.1

What are the various types of annealing? Where are they used?

Q7.2

What is the major difference in the purpose of annealing and normalizing?

Q7.3

"Hardening of steel is always followed by tempering." Is it true or false? If true, give reasons.

Q.8 Solve these questions:

Q8.1

What are the different types of composite materials available? Give their suitable examples with applications.

Q8.2

What are the most important rules for designing composite parts?

Q8.3

Write the applications of cemented carbide composite.

Q.9 Distinguish the following:

Q9.1

(a) Plain carbon steel and Alloy steel

Q9.2

(b) White cast iron and Malleable cast iron

Q9.3

(c) Grey cast iron and Spheroidal grey iron

Q9.4

(d) Eutectics and Eutectoids


2013 V4 021305

B.Tech. 3rd Semester Examination, 2013

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct answer (any seven):

Q1.1

Which is closest to the purest form of iron?

a)

Cast iron

b)

Wrought iron

c)

Grey iron

d)

Mild steel

Q1.2

The process of isothermal transformation to form bainite in steel, is known as

a)

austempering

b)

austeniting

c)

barkerising

d)

polymerization

Q1.3

Which of the following is not a permanent magnetic material?

a)

Chromium steel

b)

Silicon iron

c)

Cobalt steel

d)

Alnico

Q1.4

Which one of the following materials is viscoelastic in nature?

a)

Nylon

b)

Glass

c)

Rubber

d)

Graphite

Q1.5

If the structure of a sample consists of pearlite, cementite and free carbon, the sample may be

a)

cast iron

b)

alloy steel

c)

dead mild steel

d)

eutectoid steel

Q1.6

Pearlite is obtained when steel is

a)

quenched in oil

b)

cooled in still air

c)

slowly cooled in furnace

d)

quenched in water

Q1.7

A material having different properties in different directions, is known as

a)

isotropic

b)

amorphous

c)

austenitic

d)

anisotropic

Q1.8

Temperating of hardened steel is done to increase its

a)

ductility

b)

grain size

c)

surface condition

d)

carbon content

Q1.9

The fatigue strength of materials increases

a)

with temperature

b)

by providing scratches on the surface

c)

by providing notches

d)

by under-stressing the material

Q1.10

The capacity of a metal to exhibit considerable elastic recovery upon release, is known as

a)

toughness

b)

resilience

c)

hardness

d)

stiffness

Q.2 Solve both questions :

Q2.1

Give the classification of ceramic materials, organic materials, electrical materials and magnetic materials with their properties and applications.

Q2.2

Write short notes on: (i) Nanomaterials (ii) Biomaterials (iii) Optical fibre

Q.3 Solve these questions:

Q3.1

What is a 'phase diagram'? How is it classified? What useful information does it provide?

Q3.2

State Gibbs' phase rule. What is the minimum and maximum number of phases which could exist in a pure metal?

Q3.3

Discuss the Hume-Rothery rules for alloy formation.

Q.4 Solve this question :

Q4.1

Draw the iron-carbon phase diagram and discuss briefly the structure and properties of steel having 0.83% and 0.40% carbon when cooled from $ 1000^\circ\text{C} $ to room temperature.

Q.5 Solve both questions :

Q5.1

Draw a TTT diagram of eutectoid steel. Discuss all the transformation with the rate of cooling.

Q5.2

Why continuous cooling of plain carbon steel does not show bainite in its microstructure?

Q.6 Solve these questions:

Q6.1

What effect does a change in heating or cooling rate have upon the transformation temperature in steel?

Q6.2

Calculate the thickness of micro-constituents present in pearlite if density of ferrite and cementite is $ 7.76 \text{ gm/cc} $ and $ 7.66 \text{ gm/cc} $ respectively.

Q6.3

A steel contains 40% ferrite and 60% pearlite at room temperature. Determine the amount of total ferrite and cementite present in the alloy.

Q.7 Solve both questions :

Q7.1

What are the various types of annealing? Where are they used?

Q7.2

What is the major difference in the purpose of annealing and normalizing?

Q7.3

"Hardening of steel is always followed by tempering." Is it true or false? If true, give reasons.

Q.8 Solve these questions:

Q8.1

What are the different types of composite materials available? Give their suitable examples with applications.

Q8.2

What are the most important rules for designing composite parts?

Q8.3

Write the applications of cemented carbide composite.

Q.9 Distinguish the following:

Q9.1

(a) Plain carbon steel and Alloy steel

Q9.2

(b) White cast iron and Malleable cast iron

Q9.3

(c) Grey cast iron and Spheroidal grey iron

Q9.4

(d) Eutectics and Eutectoids


2012 021305

B.Tech. 3rd Semester Examination, 2012

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Answer any seven sub-questions (Select correct answer / Fill in the blanks):

Q1.a

The cupola is used to make

a)

pig iron

b)

steel

c)

wrought iron

d)

cast iron

Q1.b

Iron has the unique characteristic of being

a)

paramagnetic

b)

dielectric

c)

ferromagnetic

d)

ferroelectric

Q1.c

Monel metal is an alloy of ________ and ________.

Q1.d

Cermets are

a)

metals for high temperature use with ceramic like properties

b)

ceramics with metallic strength and lustre

c)

coated tool materials

d)

metal-ceramic composites

Q1.e

Nanocomposite materials are highly preferable in design considerations for their

a)

vibration resistance

b)

high resistance to crack propagation

c)

impact resistance

d)

high resilience

Q1.f

The steel products which are required to be shock resistant should have

a)

high toughness

b)

low hardness

c)

high yield stress

d)

low percentage of carbon

Q1.g

Which of the following structures has maximum hardness?

a)

Cementite

b)

Austenite

c)

Pearlite

d)

Martensite

Q1.h

An iron-carbon binary alloy has 0.5% carbon by weight. What is this alloy called?

a)

Eutectoid

b)

Eutectic

c)

Hypoeutectoid

d)

Hypereutectoid

Q1.i

As per Gibbs' phase rule, if the number of components is equal to 2, then the number of phases will be

a)

5\le 5

b)

4\le 4

c)

3\le 3

d)

2\le 2

Q1.j

Tempering temperature of most of the materials is of the order of

a)

100C to 150C100 ^\circ\text{C to } 150 ^\circ\text{C}

b)

200C to 300C200 ^\circ\text{C to } 300 ^\circ\text{C}

c)

350C to 400C350 ^\circ\text{C to } 400 ^\circ\text{C}

d)

400C to 500C400 ^\circ\text{C to } 500 ^\circ\text{C}

Q.9 Write short notes on the following:

Q9.a

Whiskers

Q9.b

Glass fibre-reinforced polymer composite

Q9.c

Tempered martensite

Q9.d

Hume-Rothery rule


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