inroduction to materials

1. Course Code – MEC304
Course Name – Materials and Metallurgy
By
Prof. O.A.Jarali
Department of Mechanical
Engineering
University of Mumbai
Second Year Mechanical Engineering

2. Objectives :
1. To familiarize the structure- property correlation in materials
2. To acquaint with the processing dependency on the performance of the
various materials
3. To study the role of alloying in the development of steel
4. To familiarize with the advances in materials development
Outcomes : Learner will be able to……
1. Identify the various classes of materials and comprehend their properties
2. Apply phase diagram concepts to engineering applications
3. Apply particular heat treatment for required property development
4. Identify the probable mode of failure in materials and suggest measures to
prevent them
5. Choose or develop new materials for better performance
6. Decide an appropriate method to evaluate different components in service

3. Module Contents Hours
1 i. Classification of materials
ii. Concepts of crystals
iii. Crystal defects
iv. Cold working and re crystallization annealing
8
2 i. Mechanism of crystallization
ii. Classification of alloys based on phases and phase diagram
iii. Iron-Iron carbide phase diagram
8
3 i. Heat treatment
ii. Surface hardening processes
iii. Alloy steels
6
4 i. Strengthening mechanisms in materials
ii. Fracture of metals
iii. Fatigue & Creep
6
5 i. Composites
ii. Nano materials
iii. Introduction to smart materials
6
6 i. Engineering polymers and ceramics
ii. Processing
iii. Non-destructive testing of materials
4

4. Experiment
No.1
Experiment Hours
1 Study of characterization techniques and metallographic
sample preparation and etching
2
2 Comparison of microstructures and hardness before and
after annealing, normalizing and hardening in medium
carbon steel 2
(Any Two)
3 Study of tempering characteristics of hardened steel
4 Determination of hardenability of steel using Jominy end
quench test (Using different hardness testers to measure
the hardness)
5 Fatigue test – to determine number of cycles to failure of
a given material at a given stress
2
Laboratory Experiments
Examination Scheme
Internal Assessment End Semester
Exam
Total
Test 1 Test 2 Average
20 20 20 80 100

5. What is a material?
A matter (which is present naturally or made artificially) from which useful
things are made…

6. Materials: The Milestones of Progress
Development and advancement of Human societies closely related with materials
 Civilizations have been named based on the level of their materials development –
Stone age, Bronze age etc.

7. Quest for newer materials: The driving force for the progress
Quest for more advanced materials to meet the growing needs as the civilization
progressed.
New Materials :
1. FR Composites
2. PR composites
3. Structural Composites
4. Laminar Composites
5. Nano materials
6. Nano composites
7. Polymers
8. Smart materials
(Rheological fluids)

8. Automobile and Materials

9. From Cast iron blocks to more compact, lighter and powerful engine blocks –
Material development has made it all possible
Engine components are traditionally made from ferrous alloys. Emphasis on
weight reduction for higher fuel efficiency has increased usage of aluminum for
cylinder blocks, cylinder heads, and other engine components.
Some engine covers and intake manifolds are made of magnesium.
Titanium is also used in high-speed engines connecting rods to reduce
reciprocating mass.
Materials like synthetic rubber, variety of polymers, foams have provided new
dimension and aesthetic look to automotive interiors
Advancement in materials -

10. On it’s maiden voyage from Southampton, UK to New York city, RMS titanic
sank in the North Atlantic on April 15, 1912 on colliding with an iceberg
An analysis done on the hull steel years later provided the materials aspects
of this tragedy.
The hull of the ship was made of riveted steel plates
The quality and the composition of the steel is crucial for
the required properties and performance.
A Case Study – Titanic Tragedy
Hull made of Riveted steel plates
Rivet joint

11. Poor Steel quality, high S and P and low Mn:S ratio
A metallurgical analysis done on the hull steel revealed a Mn:S ratio of 6.8:1
which was too low compared to a quality steel like ASTM A36 (Mn:S - 15:1)
Low Mn:S ratio cannot remove the sulfur from steel
As a result sulphides form. The brittle sulfides reduces the impact properties
At lower temperature metals and alloys loose their ductility and becomes
brittle – Ductile to Brittle Transition Temperature (DBTT) is the deciding factor
Failure analysis
Formation of brittle sulphide inclusions due to Low Mn:S ratio
High Ductile to brittle transition temperature (DBTT) – The steel became
very brittle at low temperature
Impact property testing of the titanic steel exhibited brittle behavior.
Brittle fracture on collision with ice berg in the chilling water temperature
(-2 deg. C at the time of collision).
Breakage of ship and sinking
Metallurgical aspects of failure