Sample Course File Edited 20-08-2015

1

DEPARTMENT OF MECHANICAL ENGINEERING

COMPLETE COURSE FILE (Academic year)

Course Title: MATERIAL SCIENCE AND METALLURGY

Contents Page No

1. Course details

1.1 Primary info 1

1.2 Course Content (Syllabus) 2

1.3 Text books 5

1.4 Reference books 5

2. Course plan

2.1 Course learning objectives 6

2.2 Course outcomes 6

2.3 Validation of course outcomes 7

2.4 Mapping of COs with POs 7

3. Assessment

tools and data

3.1 Definition of assessment tools 8

3.2 Assessment data 14

4. Attainment of

CO

4.1 Measuring CO attainment 44

4.2 Remarks 46

********************************

1. Course details

1.1 Primary information:

1. Course Code : 10ME32A

2. L-T-P : 4-0-0

3. Marks (Min/Max)

VTU Exam

Internal Assessment

: 50/125

35/100

0/25

4. Pre-requisite : Physics, Chemistry

5. Teaching Department : Mechanical Engineering

6. Course Duration : 52 Hours

7. Faculty Representative :

8. Course Faculty :

2

1.2 Course Content (Syllabus):

Topic Title Description Topic Level Outcomes

Duration At the end of the topic students will be able to

1. Crystal

Structure

BCC, FCC and HCP Structures

- coordination number

- atomic packing factors

Crystal imperfections

- point, line & surface imperfections

Atomic Diffusion:

- diffusion phenomenon

- Fick’s laws of diffusion

- factors affecting diffusion

1. Draw unit cells for BCC, FCC and HCP crystal

structures.

06 Hours

2. Find the atomic packing factor for BCC, FCC and

HCP crystal structures.

3. Compute the density of metals having FCC, BCC

and HCP crystal structures given their unit cell

dimensions.

4. Name and describe different crystal imperfections.

5. Describe the mechanism of atomic diffusion.

2. Mechanical

Behaviour

Stress-strain diagram showing

- ductile and brittle behaviour of

materials

- linear and nonlinear elastic

behaviour and properties

- mechanical properties in plastic

range; yield strength, offset yield

strength, ductility, ultimate tensile

strength, toughness

Plastic deformation of single crystal

- slip and twinning

1. Explain the ductile-brittle and linear-nonlinear

elastic behaviour of materials.

06 Hours 2. Evaluate the mechanical properties of a material

through stress strain diagram.

3. Identify plastic deformation by slip and twinning

in materials.

3. Failure of

Materials

Fracture:

- Type I, Type II and Type III

Creep:

1. Differentiate failure of materials by fracture, creep

and fatigue. 07 Hours

3

- description of the phenomenon with

examples

- three stages of creep

- creep properties

- stress relaxation

Fatigue:

types of fatigue loading with

examples

mechanism of fatigue

fatigue properties

fatigue testing and S-N diagram

2. Explain the different types of fracture modes,

creep stages and fatigue loading.

3. Explain the phenomenon of creep and its

properties.

4. Explain mechanism of fatigue failure for a material

and plot SN diagram.

4. Solidification

Mechanism of solidification

- nucleation

- crystal growth

- cast metal structures

Phase Diagram I

- solid solutions

- Hume Rothary rule

- substitutional and interstitial solid

solutions

- intermediate phases

- Gibbs phase rule

1. Explain the mechanism of solidification by

nucleation and grain growth for pure metals and

alloys.

07 Hours

2. Enumerate the significance of cast structure of

metals and the methods to control it.

3. Construct phase diagram for simple binary alloys.

4. Identify the formation of interstitial or

substitutional solid solutions and intermediate

phases.

5. Phase

Diagram II

Construction of equilibrium diagrams

involving complete and partial

solubility, lever rule.

Iron carbon equilibrium diagram

- description of phases

- solidification of steels and cast

irons

- invariant reactions

1. Construct the Iron-Carbon equilibrium diagram

and discuss the invariant reactions in it.

06 Hours

2. Interpret the formation of steel and cast irons using

an iron-carbon diagram

4

6. Heat treating

of metals

TTT curves

Continuous cooling curves

Heat treatment techniques

- annealing and its types,

normalizing, hardening,

- tempering, martempering,

austempering

- hardenability and surface hardening

methods like carburizing,

cyaniding, nitriding, flame

hardening and induction hardening

- age hardening of aluminium-copper

alloys

1. Explain the process details of various heat

treatment processes.

07 Hours

2. Suggest a suitable heat treatment technique for the

desired materials and properties.

7. Ferrous and

non-ferrous

materials

Properties, Composition and uses of

- Grey cast iron, malleable iron, SG

iron and steel

- Copper alloys: brasses and bronzes

- Aluminium alloys: Al-Cu, Al-Si,

Al-Zn alloys

1. State the areas of application of commonly used

engineering materials.

06 Hours

2. Suggest the selection of materials based on the

property requirements

8. Composite

Materials

Definition

Classification

types of matrix materials &

reinforcements

fundamentals of production of FRP's

and MMC's

advantages and application of

composites

1. Explain the production techniques for some

common FRP’s and MMC’s

07 Hours

2. List out the advantages and applications of

composite materials

5

1.3 Text Books:

1. Foundations of Materials Science and Engineering, Smith, 4th Edition McGraw Hill,

2009

2. Materials Science, Shackleford., & M. K. Muralidhara, Pearson Publication – 2007.

1.4 Reference Books:

1. An Introduction to Metallurgy; Alan Cottrell, Universities Press India Oriental Longman

Pvt. Ltd., 1974.

2. Engineering Materials Science, W.C.Richards, PHI, 1965.

3. Physical Metallurgy; Lakhtin, Mir Publications.

4. Materials Science and Engineering, V.Raghavan, PHI, 2002.

5. Elements of Materials Science and Engineering, H. VanVlack, Addison- Wesley Edn.,

1998.

6. Materials Science and Engineering, William D. Callister Jr., John Wiley & Sons. Inc, 5th

Edition, 2001.

7. The Science and Engineering of Materials, Donald R. Askland and Pradeep.P. Phule,

Cengage Learning, 4lh Ed., 2003.

6

2. Course plan

2.1 Course Learning Objectives (CLOs):

1. To impart knowledge on structure property correlations for commonly used engineering

materials.

2. To help the students to understand the mechanical behavior, deformation characteristics

and the modes of failure of materials.

3. To enable the students to understand the effect of solidification mechanism of metals on

the resulting microstructure and properties as well as effect of subsequent heat treatments

on the material properties.

4. To train the students to interpret the iron carbon equilibrium diagram for the formation of

steel and cast irons.

5. To educate the students about the conventional engineering materials, their characteristics

and applications as well as the recent trends in materials such as composites.

6. To kindle an enthusiasm among the students to carry on lifelong learning in the field of

metallurgical and materials science.

2.2 Course Outcomes (COs):

At the end of the course the students will be able to

1. Explain the crystal structure of commonly used engineering materials and their

characteristic properties.

2. Interpret the deformation characteristics and behavior of materials when subjected to

loads till their failure.

3. Explain the solidification mechanism and heat treatment techniques and the control

measures to obtain a suitable microstructure for specific property applications.

4. Indicate the properties, composition and applications of ferrous, non-ferrous materials

and composite materials and suggest a suitable material for specific applications.

7

2.3 Validation of Course Outcomes

Course Outcome POs-Levels Cognitive Level

CO1

Explain the crystal structure of commonly used

engineering materials and their characteristic

properties.

PO1:2 Understanding

(Level 2)

CO2

Interpret the deformation characteristics and

behavior of materials when subjected to loads till

their failure.

PO1:2

PO5:1

Analyzing

(Level 4)

CO3

Explain the solidification mechanism and heat

treatment techniques and the control measures to

obtain a suitable microstructure for specific

property applications.

PO1:3

PO2:1

Applying

(Level 3)

CO4

Indicate the properties, composition and

applications of ferrous, non-ferrous materials and

composite materials and suggest a suitable material

for specific applications.

PO5:2 Understanding

(Level 2)

POs-Levels: 1-Slightly, 2-Moderately, 3-Highly

Cognitive Levels: 1 to 6 as per Bloom’s Taxonomy

2.4 Mapping of COs with POs

PO1

(a)

PO2

(b)

PO3

(c)

PO4

(d)

PO5

(e)

PO6

(f)

PO7

(g)

PO8

(h)

PO9

(i)

PO10

(j)

PO11

(k)

PO12

(l)

PO13

(m)

CO1 X

CO2 X X

CO3 X X

CO4 X

X X X X

8

3. Assessment tools and data

3.1 Assessment tools

The assessment tools to be used for CAY are;

Internal assessment

Assignments

Quizzes

I. Internal Assessment:

Internal Test – I (Date)

Q.No Question Expected Outcome Cognitive

Level Marks

TLO

Measured

1 What is packing factor? Find the packing factor for

FCC?

Refer Appendix – I

(IA Scheme and Solutions)

Remembering 5 1.2

2 What is diffusion? Explain the unsteady state of

diffusion with example?

Understanding 4 1.5

3 Differentiate between ductile and brittle material? Name

five examples for each?

Understanding 5 2.1

4 The unit cell of chromium is cubic and contains 2

atoms. Determine the dimension of the dimension of the

chromium unit cell and atomic radius. Given atomic

weight of chromium=52 & density of chromium=7.19

g/cm3

Applying 3 1.3

5 (a) A Steel rod of 10mm die & 1.5m length is subjected to

an axial tensile test of 10KN. Determine (a) Stress (b)

strain (c) Elongation. Take E=205*106 KN/m

2

Applying 5 2.2

5 (b) Explain any one of this (a) Edge dislocation (b) screw

dislocation.

Understanding 3 2.3

9

Internal Test – II (Date)


Level Marks

TLO

Measured

1 Explain Hume-Rothary rules governing the formation of

substitutional solid solution



Remembering 5 4.4

2 Explain the mechanism of solidification for pure metals. Understanding 7 4.1

3 a) Draw Fe-Fe3C phase diagram and label all the regions

indicating the invariant reactions with the temperature

and composition for the same.

b) From the above phase diagram calculate the amount of

eutectic present in the pearlite using lever rule.

c) Also sketch the typical microstructure for the

following

(i) eutectoid steel at room temperature

(ii) hypo-eutectic cast iron having 3% carbon at 910

C and at room temperature

Remembering

Understanding

Understanding

8

2

3

5.1

4 a) Explain with neat sketch the different stages of creep

formation?

Understanding 8 3.2

b) What is fatigue failure? Draw S-N curve for steel and

aluminum?

Understanding 5 3.4

Internal Test – III (Date)


Level Marks

TLO

Measured

1 a) From fundamentals distinguish clearly between alloy

and composites.



Understanding 3 6.2

b) Classify the composites based on the matrix and

reinforcements.

Remembering 3 6.1

2 List down the production methods of metal matrix

composites. Explain any one with neat sketch.

Understanding 5 6.1

3 What is meant by heat treatment? What are its

objectives?

Remembering 4 8.1

10

4 Define hardenabilty. Explain the process which is used

to find the hardenability of steel.

Understanding 5 8.2

5 What is Case hardening? Explain pack carburizing

process.

Understanding 5 8.1

II. Assignments:

A.

No Questions

Cognitive

Level

TLO

Measured

Date of

Submission

1

1. What are the three primary bonds in materials? Which is the strongest? Why? Remembering

Date

2. Find out from the Handbook of materials the melting points of the following metals and

cite the details of the handbook referred.

a) Plain Carbon Steel (0.3 % Carbon)

b) Aluminium

c) Magnesium

d) Copper

understanding

3. How does the mechanical property (strength and ductility) of a material vary with its grain

size? Explain. (Refer Hall-Petch Relation) Understanding 2.1

4. How does the presence of defects in a crystal structure and alloying alter the properties of a

material? Explain. Analyzing 1.4

5. Explain strain hardening. Understanding 2.3

6. Explain how grain boundaries impede dislocation motion and why a metal having small

grains is stronger than one having large grains. Analyzing 2.3

7. Following are the tensile test results of a steel specimen having a 30 mm diameter and 200

mm length. Extension at a load of 50kN = 0.1mm. Load at elastic limit = 230kN.

Maximum load = 300kN. Total extension = 50 mm. Diameter of rod at failure = 20 mm.

Calculate (i) Young's modulus (ii) Ductility

Applying 2.2

8. A low carbon steel rod is subjected to tensile load of 7000 kg. Assuming no volume change

during extension, determine (i) Engineering stress and engineering strain. (ii) True stress

and true strain. The initial diameter of the rod is 13 mm and after application of load

12mm.

Applying 2.3

2

1. What do you mean by alloying? How is it different from a pure metal with reference to

mechanical properties and microstructure? Understanding 4.1

Date 2. Why is undercooling necessary for nucleation? Explain the concept of volume free energy

and surface free energy with its effect on undercooling for homogeneous and

heterogeneous nucleation.

Understanding 4.1

11

3. What is a phase diagram? Why is it necessary? Understanding 4.3

4. Explain phase rule and lever rule with emphasis on a binary eutectic phase diagram. Understanding 4.4

5. Sketch the typical microstructure for the following at room temperature: (a) Pure iron (b) Plain carbon steel with 0.4 % carbon (c) Eutectoid steel (d) Cast iron with 4.5 % carbon

Remembering 5.2

6. Plot the eutectic region of a Fe-Fe3C system and find the eutectic present in an alloy of 3.5

%C at 1000 C. Analyzing 5.1

7. What is an Invariant reaction? Draw the pictorial representation of the following invariant reactions:

(a) Eutectic reaction (b) Eutectoid transformation (c) Peritectic reaction

Analyzing 5.1

III. Quizzes:

Quiz 1

SL

No. Questions Answer

TLO

Measured

1. Repeatable entity of a crystal structure is known as

(a) Crystal (b) Unit cell (c) Grain (d) Lattice

Unit Cell 1.1

2. Atomic packing factor is

(a) Volume fraction of atoms in a unit cell (b) Projected area fraction of atoms on a plane

(c) Distance between two adjacent atoms (d) None

Volume

fraction of

atoms in a unit

cell

1.2

3. Choose the correct lattice parameters for a hexagonal crystal system

(a) a=b=c , α=β= 0deg, γ=120deg (b) a=b≠c , α=β=90deg, γ=120deg

(c) a=b=c , α=β=γ=120deg (d) a=b≠c , α=β=γ=120deg

a=b≠c ,

α=β=90deg,

γ=120deg

1.3

4. Following is not the 2-dimensional imperfection

( ) Di location (b) Grain boundary (c) Twin boundary (d) External surface

Dislocation 1.4

5. The yield strength for a material with well-defined elastic to plastic transition showing an upper and lower

yield point is measured as

(a) stress at 0.2% offset strain (b) average of stresses at upper and lower yield point

average stress at

lower yield

point

2.1

12

(c) average stress at lower yield point (d) stress at upper yield point

6. For a tensile experiment the ductility is measured as

(a) percentage elongation in length (b) percentage reduction in area

(c) both (d) None of the above

both 2.2

7. Plastic deformation results from the following

(a) Slip (b) Twinning (c) Both (d) None

Both 2.3

Quiz 2

SL

No. Questions Answer

TLO

Measured

1 The slow and progressive deformation of a material with time at constant stress is known as Creep 3.1

(a) Fracture (b) Fatigue (c) Creep

2 Usually materials with following crystal structure fail in ductile mode FCC 3.2

(a) HCP (b) FCC (c) BCC (d) None

3 Creep rate in ternary stage Increases 3.3

(a) Decreases (b) Increases (c) Constant (d) None

4 SN curve gives information about Fatigue 3.4

(a) Fatigue (b) Creep (c) Failure (d) All

5 For homogeneous nucleation occurs in the presence of Undercooling

(a) Impurities (b) Undercooling (c) Both (a) & (b) (d) None 4.1

6 As the grain size decreases the hardness of a material Increases 4.2

(a) Decreases (b) Increases (c) Has no effect (d) None

7 A binary phase diagram is a plot of Temp. Vs

Composition

4.3

(a) Temp. Vs Time (b) Temp. Vs

Composition

(c) Temp. Vs Pressure (d) None

8 Eutectoid reaction can be represented as 4.4

(a) (b) (c) (d)

9 Maximum percentage of carbon in austenite is 5.1

(a) 0.02 % (b) 0.8 % (c) 2.1 % (d) 4.3 % 2.1 %

10 The upper critical temperature for steel 5.2

13

(a) varies with carbon

%

(b) is constant (c) depends on rate

of heating

(d) none of these varies with

carbon %

11 Annealing of steel is done

(a) to soften the metal (b) improve

machinability

(c) refine grain size (d) all of these all of these 6.1

12 Suggest a suitable heat treatment to increase hardness without resorting to severe quenching. Martempering 6.2

(a) Annealing (b) Normalizing (c) Martempering (d) Carburizing

13 Bronze is an alloy of Copper & Tin 7.1 & 7.2

(a) Copper & Zinc (b) Copper & Tin (c) Iron & Brass (d) Iron & Zinc

14 Which of the following is a continuous production technique used for production of FRP Pultrusion

(a) Filament winding (b) Vacuum bag moulding (c) Spray up process (d) Pultrusion 8.1

15 The function of a matrix phase in a composite is Both (a) and (b) 8.2

(a) Improve impact and fracture resistance (b) Provide strength and stiffness to composite

(c) Both (a) and (b) (d) None

14

3.2 Assessment data:

I Internal Assessment Marks

Sl. No. USN Name

Marks Scored

Q. No. 1 2 3 4 5 [a] 5 [b]

Max 5 4 5 3 5 3

5 0 1 0 1 2

5 2 5 1 2 2

5 0 0 0 0 1

5 1 5 2 5 1

5 4 5 3 5 3

5 1 NA 0 3 1

5 4 5 3 5 3

5 4 5 2 5 3

5 1 3 0 5 3

4 4 4 3 5 3

5 4 5 3 5 3

5 2 5 0 3 2

NA 1 2 1 NA 3

4 1 5 NA 2 0

3 2 2 0 5 3

5 1 1 0 NA 1

3 3 1 1 1 3

5 4 5 3 5 3

5 1 4 1 4 3

5 4 5 1 5 3

5 1 5 1 NA 3

5 1 5 0 5 3

5 4 5 3 4.5 3

5 1 4 1 1 3

5 2 5 0 1 3

5 4 5 3 5 3

5 4 4 3 5 2

5 1 5 0 2 2

5 4 5 3 3 3

5 1 5 3 5 3

5 1 4 1 2 0

5 4 5 3 5 3

870 289 712 266.5 649 396.5

Average Marks 4.10 1.55 3.39 1.46 3.12 2.02

Avearage Marks (Percentage) 82.08 38.84 67.81 48.81 62.40 67.43

TLO/s which is/are assessed by the question 1.2 1.5 2.1 1.3 2.2 2.3

Total Marks

19

II Internal Assessment Marks

Sl. No. USN Name

Marks Scored

Q. No. 1 2 3 4 [a] 4 [b]

Max 5 7 13 8 5

5 3 NA NA NA

5 6 NA 8 3

5 3 2 NA NA

5 3 12 NA NA

5 4 10 NA NA

5 7 NA NA 5

5 4 NA 8 2

5 5 5 NA NA

0 6 NA 8 2

5 5 5 NA NA

5 5 8 NA NA

5 4 NA 8 4

5 4 NA NA NA

3 5 NA 4 1

5 5 0 NA NA

5 4 10 NA NA

5 6 NA 8 4

5 7 13 NA NA

4 2 4 NA NA

5 3 NA 8 5

5 6 NA 7 1

5 5 NA 8 5

5 7 11 NA NA

5 3 NA 8 3

5 3 NA 6 5

Total Marks 912 912 971.5 700 442.5

Average Marks 4.36 4.51 6.75 5.88 3.75

Avearage Marks (Percentage) 87.27 64.50 51.90 73.53 75.00

TLO/s which is/are assessed by the question 4.4 4.1 3.2 3.4

Average Marks

Avearage Marks (Percentage)

TLO/s which is/are assessed by the question 5.1 & 5.2

24

III Internal Assessment Marks

Sl. No. USN Name

Q. No. 1 [a] 1 [b] 2 3 4 5

Max 3 3 5 4 5 5

0 NA 0 1 NA NA

NA NA NA NA NA NA

3 0 5 1 0.5 4

2 2.5 5 4 NA 5

NA NA NA NA NA NA

NA NA 5 NA NA NA

NA NA NA NA NA NA

2 0 4 1 4 3

NA NA NA NA NA NA

3 1 4 1 1 NA

2 2.5 5 4 5 5

NA NA NA NA NA NA

2.5 2 0 NA 5 NA

2.5 0 4 4 1 1

2.5 1.5 0 4 5 0

1.5 0 4 0 0 0

Total Marks 136 107 197 203.5 349 170

2.00 1.81 2.94 3.04 2.81 2.66

Avearage Marks (Percentage) 66.67 60.45 58.81 75.93 56.29 53.13

TLO/s which is/are assessed by the question 8.2 8.1 8.1 6.1 6.2 6.1

Average Marks

Avearage Marks (Percentage)

TLO/s which is/are assessed by the question

30

Quiz 1 Result

Sl.No. USN Name Quiz score

1 2 3 4 5 6 7

0 0 0 1 0 0 0

1 1 0 0 0 1 0

1 1 1 0 0 0 0

1 1 1 0 0 1 1

1 1 1 0 0 1 1

0 0 1 0 1 1 1

1 1 1 1 0 0 0

0 0 0 0 1 1 1

0 1 0 0 0 0 1

0 0 0 0 0 1 1

1 1 1 1 1 1 1

1 1 0 0 0 0 1

0 0 0 1 0 1 1

1 1 0 0 0 0 0

0 0 1 0 0 1 1

0 0 0 0 1 0 1

Average Marks (Percentage) 62% 51% 50% 36% 19% 53% 67%

1.1 1.2 1.3 1.4 2.1 2.2 2.3 TLOs Assessed by the question

34

Quiz 2 Result

Sl. No. USN Name Quiz score

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

0 0 1 1 1 1 1 0 1 1 0 0 0 1 0

0 0 1 1 1 1 0 1 0 0 0 1 0 0 0

0 0 0 1 0 1 0 0 0 0 0 0 1 1 0

1 0 1 1 1 1 1 0 1 1 1 1 1 0 0

1 1 0 1 0 1 1 1 0 0 1 0 1 0 0

USN NameQuiz score

Average Marks (Percentage) 43 33 58 52 48 74 68 34 30 50 44 25 47 21 17

TLOs Assessed by the question 3.1 3.2 3.3 3.4 4.1 4.2 4.3 4.4 5.1 5.2 6.1 6.2 7.1&7.2 8.1 8.2

43

5 5

3 4

4 5

4 5

4 4

Total Marks 586 575

Average Marks 3.93 3.86

Avearage Marks (Percentage) 78.66 77.18

TLO/s which is/are assessed by the question 1.4, 2.1, 2.2, 2.3 4.1, 4.3, 4.4, 5.1, 5.2

Assignment Marks

Sl. No. USN Name

Marks Scored

Assigment No. A1 A2

Q. No. (8 Questions) (7 Questions)

Max 5 5

3 2

5 5

3 4

5 3

5 5

4 3

5 2

5 3

5 5

Sudarshan Rao

Line

44

4. Attainment of Course Outcomes

4.1 Measuring CO attainment:

TLO

No. Topic Learning Outcome

Attained

Level of

Bloom's

Taxonomy

Assessment

Tool Used Weightage

Percentage

Average

Assessment

Contribution to CO

Attainment

Attainment

Goal CO1 CO2 CO3 CO4

1.1 Draw unit cells for BCC, FCC and HCP crystal

structures.

Remembering Quiz 1 0.25 62.22 15.56

1.2 Find the atomic packing factor for BCC, FCC

and HCP crystal structures.

Applying IA 1 0.25 82.08 20.52

1.3 Compute the density of metals having FCC, BCC and

HCP

crystal structures given their unit cell dimensions.

Applying

Quiz 1 0.25 49.63 12.41

1.4 Name and describe different crystal imperfections. Remembering Quiz 1 0.25 35.56 8.89

2.1 Explain the ductile-brittle and linear-nonlinear elastic

behaviour

of materials.

Understand

IA 1 0.2 67.81

13.56

2.2 Evaluate the mechanical properties of a material

through

stress strain diagram.

Analyzing

IA 1 0.2 62.40

12.48

2.3 Identify plastic deformation by slip and twinning in

materials.

Understanding IA 1 0.1 67.43

6.74

3.1 Differentiate failure of materials by fracture, creep and

fatigue.

Understanding Quiz 2 0.1 43.14

4.31

3.2 Explain the different types of fracture modes, creep

stages

and fatigue loading.

Understanding

IA 2 0.2 73.53

14.71

3.3 Explain the phenomenon of creep and its properties. Understanding Quiz 2 0.1 57.84

5.78

3.4 Explain mechanism of fatigue failure for a material and

plot SN diagram.


7.50

4.1 Explain the mechanism of solidification by nucleation

and grain growth for pure metals and alloys.


6.45

4.2 Enumerate the significance of cast structure of metals

and the methods to control it.

Applying Quiz 2 0.1 73.53

7.35

4.3 Construct phase diagram for simple binary alloys. Remembering Quiz 2 0.1 67.65

6.76

45

4.4 Identify the formation of interstitial or substitutional

solid solutions and intermediate phases.


8.73

5.1 Construct the Iron-Carbon equilibrium diagram

and discuss the invariant reactions in it.


10.38

5.2 Interpret the formation of steel and cast irons

using an iron-carbon diagram


5.00

6.1 Explain the process details of various heat treatment

processes.


15.19

6.2 Suggest a suitable heat treatment technique for

the desired materials and properties.


5.63

7.1 State the areas of application of commonly used

engineering materials.

Remembering Quiz 2 0.2 47.06

9.41

7.2 Suggest the selection of materials based on the

property requirements


9.41

8.1 Explain the production techniques for some

common FRP’s and MMC’s


18.14

8.2 List out the advantages and applications of

composite materials

Remembering IA 3 0.3 66.67

20.00

Total Attainment of CO1 57.37

65

Total Attainment of CO2

65.09

65


65.49

65


56.96 65

46

4.2 Remarks:

Course Coordinator:

Module Coordinator:

(Course & Module Coordinator)

(HOD – Mech Dept)

47

Appendix – I

(IA Scheme & Solutions)

I Internal Assessment - Scheme of evaluation & Solution

Q.No Solution Marks

1. What is packing factor? Find the packing factor for FCC? 5

Atomic Packing Factor

The Atomic Packing Factor (APF) is the fraction of volume in a crystal

structure that is occupied by the atoms.

i.e., APF =

= =

(1)

FCC:

From ABC,

AC2+BC

2= AB

2

2 +

2 =

2

=

Number of atoms per unit cell, = 4

Volume of each atom, =

Volume of a unit cell, =

Therefore,

APF = =

APF = 0.74

i.e., 74 % of the space available in a FCC unit cell is occupied by atoms.

(4)

48

2. What is diffusion? Explain the unsteady state of diffusion with example? 4

Atomic diffusion

From an atomic perspective diffusion may be defined as the mass flow

process by which atoms or molecules migrate from lattice site to lattice site

within a material resulting in the uniformity of composition as a result of

thermal agitation.

(1)

Fick’s second law of diffusion:

Most practical diffusion situations are usually of unsteady state. i.e., the

diffusion flux and the concentration gradient at some particular point in

solid vary with time resulting in net accumulation or depletion of

diffusing species.

Therefore, =

Where,

= rate of composition change

= co ncentration gradient

D = diffusivity, m2/s

Fig: Concentration profile for unsteady state diffusion

If diffusion coefficient is independent of concentration;

= D

i.e., the rate of composition change is equal to the diffusivity times the rate of

concentration gradient.

The solution to the above equation can be obtained by applying appropriate

boundary conditions.

Fort = 0, C = C0 (0 x ∞)

For t > 0, C = Cs (at x = 0) and C = C0 (at x = ∞)

Applying the above boundary conditions the solution can be obtained as,

= 1 – erf

From the above equation may be determined at any time and position if the

parameters and D are known

(3)

3. Differentiate between ductile and brittle material? Name five examples for

each?

5

49

Ductile Brittle

Materials can withstand larger strain

before fracture

Material fracture at lower strain

Large amount of yielding and yield

point in some cases

No yield point and less yielding

Low young’s modulus and ultimate

stress

Comparatively large

Capable of absorbing large quantities

of energy before fracture

Comparatively small

Necking is observed before fracture Catastrophic failure without warning

Ex: steel, aluminum, gold etc Ex: glass, cast iron, concrete etc

4. The unit cell of chromium is cubic and contains 2 atoms. Determine the

dimension of the dimension of the chromium unit cell and atomic radius.

Given atomic weight of chromium=52 & density of chromium=7.19 g/cm3

Solution : chromium = cubic structure

Atomic data= A=52

Density = =7.19 Mgm-3

V=2.401*10

-23 cm

3

w.k.t cubic structure, volume=V=a3

a=0.288nm

3

5.a) A Steel rod of 10mm die & 1.5m length is subjected to an axial tensile test

of 10KN. Determine (a) Stress (b) strain (c) Elongation. Take E=205*106

KN/m2

5

Solution : original dia=do=10mm

Original length=Lo=1.5m=1.5*103mm

Load =P=1KN

E=205*106 kN/m

2

(3)

50

w.k.t (Youngs modulus)

(1)

Elongation (

w.k.t stain( =

(1)

5.b) Explain any one of this (a) Edge dislocation (b) screw dislocation.

Edge Dislocation

It is created in a crystal by insertion of an extra plane of atoms i.e., a half plane

as shown in figure. The edge of the half plane terminates within the crystal, this

is termed as dislocation line. The atoms above the dislocation line are squeezed

together and are in a state of compression while the atoms below are pulled

apart and are in a state of tension. Edge dislocation is represented by the

symbol ┴ for positive dislocation and ┬ for negetive dislocation.

Screw Dislocation

It is said to be formed in perfect crystal when part of the crystal displaces

angularly over the remaining part under the action of shear stress. The upper

front region of the crystal is shifted one atomic distance to the right relative to

the bottom portion. The screw dislocation derives its name from the spiral or

helical path that is traced around the dislocation line by the atomic planes of

atoms. Screw dislocation is represented by the symbol for clockwise or

positive dislocation and for counterclockwise or negtive dislocation.

3

51

II Internal Assessment

Q.No Solution Marks

Answer both questions from Part A and any one from Part B.

Part A

1. Explain Hume-Rothary rules governing the formation of substitutional

solid solution.

5

These are the rules governing the formation of substitutional solid solutions;

1) Crystal structure factor: for complete solid solubility of two elements, they

should have the same type of crystal structure.

2) Relative size factor: the atoms of the solute and the solvent should be

approximately of the same size (difference in radii should be less than

15%).

3) Chemical affinity: the two metals should have very less chemical affinity.

4) Electronegativity (tendency to acquire electrons): the two metals should

have less electronegativity; higher the electronegativity of two elements

greater will be the chance of forming an intermediate phase.

5) Relative valence factor: among the metals, the one with the lower valency

tends to dissolve more of a metal of higher valency than vice versa. For

example, in a Ni-Al system; Ni has valency of 2 which dissolves 5% Al,

but Al has valancy of 3 and dissolves only 0.04% Ni.

(5x1)

2. Explain the mechanism of solidification for pure metals. 7

Solidification in pure metals

Pure metals have a clearly defined melting or freezing point. i.e., it solidifies at

a constant temperature.The evolution of latent heat is associated with

solidification and as a result temperature remains constant. An equilibrium

cooling of pure metal maybe assumed as shown in figure 3.9. It is also seen that

if a pure metal is cooled rapidly or otherwise when it is very pure it may cool

with some amount of undercooling.

52

Dendritic growth

Pure metals solidifying with a negative temperature gradient may result in

uneven projection of interface due to the thermal undercooling. The tip of the

projection is at a region of greater undercooling than the remainder of the

interface and will have a tendency to grow further into the liquid. The solids

grow in a stem perpendicular to the surface. The latent heat evolved tends to

lower the amount of undercooling at the main interface. The protrusion grows

into a spike while the growth of main interface is somewhat retarded. The spike

grows and branches develop on it, this branched structure is known as a

dendrite. The rate of dendritic growth depends upon the amount of

undercooling in the liquid ahead of the advancing dendrite.

Part B

3.a) Draw Fe-Fe3C phase diagram and label all the regions indicating the invariant

reactions with the temperature and composition for the same.

8

(6+2)

3.b) From the above phase diagram calculate the amount of eutectic present in the

pearlite using lever rule.

2

3.c) Also sketch the typical microstructure for the following

(i) eutectoid steel at room temperature

(ii) hypo-eutectic cast iron having 3% carbon at 910 C and at room

temperature

3

4.a) Explain with a neat sketch the different stages of creep formation? 8

Explanation

(4)

53

(4)

4.b) What is fatigue failure? Draw S-N curve for steel and aluminium? 5

Explanation

(2)

(3)

III Internal Assessment

Q.No Solution Marks

1.a) From fundamentals distinguish clearly between alloy and composites. 3

In an alloy, the element getting introduced (solute) dissolves into the metal

getting alloyed (solvent) to form a solid solution. It is a kin to salt dissolving in

water to form a salt solution except that the alloy is in solid form. One cannot

distinguish them.

In the case of composite, the metal forming the base of the composite (matrix)

and the added element remain un dissolved and could be identified. In the case

of metal matrix composite, one finds carbon fibers or a ceramic material in the

matrix of metal.

1.b) Classify the composites based on the matrix and reinforcements. 3

54

Classification based on Reinforcements

2. List down the production methods of metal matrix composites. Explain

any one with neat sketch.

5

For listing out production methods -1 marks

For sketch-2 marks

For explanation-2 marks.

3. What is meant by heat treatment? What are its objectives? 4

Heat treating is a group of industrial and metalworking processes used to alter

the physical, and sometimes chemical, properties of a material. The most

common application is metallurgical.

(1)

http://en.wikipedia.org/wiki/Industrial_process

http://en.wikipedia.org/wiki/Metalworking

http://en.wikipedia.org/wiki/Physical_property

http://en.wikipedia.org/wiki/Chemical_property

http://en.wikipedia.org/wiki/Metallurgy

55

Objectives – (at least three) (3)

4. Define hardenabilty. Explain the process which is used to find the

hardenability of steel.

5

Definition-1 marks

Sketch-2 marks

Explanation-2 marks

5. What is Case hardening? Explain pack carburizing process. 5

Definition-1 marks

Sketch-2 marks

Explanation -2 marks

Documents

Sample Course File Edited 20-08-2015