ENG’G 1021

MATERIAL SCIENCE & INTRODUCTION

ENGINEERING FOR CHEM E
Historical timeline of materials

• Materials science has shaped the development of

civilizations since the dawn of mankind.

• Better materials for tools and weapons have allowed

mankind to spread and conquer, and

• advancements in material processing like steel and

aluminum production continue to impact society today
Historical timeline of materials

• Historians have regarded materials as such an important

aspect of civilizations such that entire periods of time
have defined by the predominant material used.

• As such you have met the words:

• Stone age
• Copper age
• Bronze age
• Iron age, etc
Historical timeline of materials

• For most of recorded history, control of materials had

been through alchemy or empirical means at best.

• The study and development of chemistry and physics

assisted the study of materials,

• and eventually the interdisciplinary study of materials

science emerged from the fusion of these studies.
Historical timeline of materials

‣ The history of materials science is the study of how

different materials were used and developed
through the history of Earth.

‣ The term "Silicon Age" is sometimes used to refer

to the modern period of history during the late 20th
to early 21st centuries.
•End
MATERIALS FOR
ENGINEERING

Materials Science vs Materials Engineering

 BASIC DEFINITIONS

• Materials Science: investigates the relationships that exist

between the structure and properties of materials

• Materials Engineering: involves designing or engineering the

structure of a material to produce a predetermined set of
properties
 SPECIFIC ROLES

• Materials Scientist: the role is to develop or synthesize new

materials

• Materials Engineering:
• create new products using existing materials
• develop systems or techniques in the processing of materials
 STRUCTURE OF A MATERIAL

• Structure – refers to the arrangement of a materials internal

components
• 4 types of structures:
• subatomic - involves electrons & their interaction with the nuclei
• atomic - organization of atoms or molecules relative to one another
• microstructure - group of atoms that can be seen by a microscope
• macrostructure - structural elements that can be seen by the eye
 BUT WHY STUDY MATERIALS
SCIENCE/MATERIALS ENGINEERING?

• Because an engineer is always exposed to design problems

involving materials!

• In todays’ industry, selecting the right material from many

available is of paramount importance.
 FOR EXAMPLE, WHICH CONTAINER IS
THE BEST?

• COKE IN CAN? • COKE IN PLASTIC

CONTAINER?
 WHICH IS THE BEST….

• OR COKE IN BOTTLE?
TO ANSWER THAT QUESTION, YOU
NEED CRITERIA!
CRITERIA FOR THE SELECTION OF
MATERIALS
 1 ST CRITERIA

• The in-service condition of the materials should be

characterized.
• How will it be used?
• What are the required properties?
Example: strength or ductility?
In short, the required properties should be specified.
 2 ND CRITERIA

• Deterioration of the material properties during operation, in

short, wear-and-tear…
• Do not expect a material to last a lifetime. As time goes by, there is a
reduction in a material’s properties due to constant use or exposure
to the elements.
 3 RD CRITERIA

• Economics:
• Quality vs Cost

• This is always a problem in material selection

• Would you pick an expensive but durable material or
• a cheap but less expensive one?
MATERIAL PROPERTIES
 WHAT IS A MATERIAL PROPERTY?

• While in use a material is subjected to an external

stimulus that results in a particular response.
• Ex. A metal deforms when subjected to a force
• The same metal expands when heated
 THE SIX(6) IMPORTANT MATERIAL
PROPERTIES

• Mechanical properties - express the relationship of

deformation to the applied load or force

• Ex. Stiffness, strength, toughness, ductility

 PROPERTIES…

• Electrical properties - express the response of a

material to an electric field

• Electrical conductivity, dielectric constant

 PROPERTIES…

• Thermal properties - express the response of the

material to heat

• Heat capacity, heat conductivity

 PROPERTIES…

• Magnetic properties - express the response to a

magnetic field
 PROPERTIES…

• Optical properties - response of the material to

electromagnetic or light radiation

•Ex. Index of refraction, reflectivity

 DIFFERENT OPTIC AL
PROPERTIES

Can you guess them?

 PROPERTIES…

• Deteriorative (chemical) properties - refers to the

chemical reactivity of the material
THE FOUR(4) COMPONENTS INVOLVE IN
THE SCIENCE & ENGINEERING OF
MATERIALS
C AN YOU EXPLAIN THE RELATIONSHIP AMONG THE
FOUR COMPONENTS?
END
CLASSIFICATION OF FIVE GROUPS
MATERIALS
THE MAJOR GROUPS

 Metals
 Ceramics
 Polymers
 Composites
 Advance materials
METALS

 are made up of one or more metallic elements (Fe, Al,

Cu, Au) and often also non-metallic elements (C, Ni, O)
in small amounts.
 atoms in metals are arranged in an orderly manner
 dense compared with other materials
 stiff and strong yet ductile, resistant to fracture
METALS…

 good conductors of electricity and heat

 not transparent to visible light
 some metals have good magnetic properties
 • Properties depend on structure

STRUCTURE,ex:PROCESSING,
hardness vs structure of steel
& PROPERTIES
(d)
6 00

Hardness (BHN)
30 mm
5 00 (c)
Data obtained from Figs. 10.30(a)
4 00 (b) and 10.32 with 4 wt% C composition,
(a) and from Fig. 11.14 and associated
4 mm discussion, Callister & Rethwisch 8e.
300 Micrographs adapted from (a) Fig.
10.19; (b) Fig. 9.30;(c) Fig. 10.33;
30 mm
and (d) Fig. 10.21, Callister & Rethwisch 8e.
2 00 30 mm

100
0.01 0.1 1 10 100 1000
Cooling Rate (ºC/s)
• Processing can change structure
ex: structure vs cooling rate of steel
6
CERAMICS

 are compounds between metallic and non-metallic

elements
 usually oxides, nitrides and carbides
 Al2O3 (alumina), SiO2 (silicon oxide), SiC (silicon
carbide), etc.
CERAMICS…

 clay minerals, cement and glass

 stiff, strong and very hard
 extremely brittle and susceptible to fracture
CERAMICS…

 insulative to the passage of electricity & heat

 greater resistance to heat and harsh environments than
metals or polymers
 may be transparent, translucent or opaque
 some oxide ceramics exhibit magnetic behavior
• Transmittance:
OPTICAL
-- Aluminum oxide may be transparent, translucent, or
opaque depending on the material structure.

polycrystal: polycrystal:
single crystal low porosity high porosity

Adapted from Fig. 1.2,

Callister & Rethwisch 8e.
(Specimen preparation,
P.A. Lessing; photo by S.
Tanner.)

11
POLYMERS

 many are organic compounds that are chemically based on carbon,

hydrogen, and other non-metallic elements (e.g. O, N, Si)
 very large chain-like molecular structures often carbon
 not as stiff or as strong as the other materials
 extremely ductile and pliable (i.e. easily formed into complex
shapes)
POLYMERS…

 chemically inert and unreactive in many environments

 soften and decompose at elevated temperatures
 low electrical conductivities
 non-magnetic
COMPOSITES

 made up of two or more materials of the previous

categories
 the objective is to have a combination of properties not
available in any single material
 also incorporates the best characteristics of the
materials
COMPOSITES…
 example is fiberglass which are glass fibers embedded in a
polymeric material: glass is strong but still while polymers are
flexible
 CFRP – carbon fiber reinforced polymer: carbon is stiff and
stronger than glass; more expensive than fiberglass
 CFRP are used in aircraft, sporting equipment, bicycles, skis,
automobile bumpers
ADVANCED MATERIALS
 are materials used in high technology applications
 high technology – a device or product that uses intricate
and sophisticated principles
 Ex. Computers, fiber-optic systems, electronic
equipment, spacecraft, rocketry, semiconductors,
biomaterials
SEMIC0NDUCTORS

 have electrical properties that are intermediate between

conductors (metals, metal alloys) and insulators
(ceramics, polymers)
 electrical properties are very sensitive to the presence
of minute concentrations of impurity atoms
BIOMATERIALS

 materials used to replace deceased or damaged body

parts
 non-toxic and compatible with body tissues (i.e. must
cause adverse biological reactions)
SMART (INTELLIGENT) MATERIALS

Two components
 are materials that are able to  Sensor – detects an input signal
sense changes in their
environment and respond to  Ex. Optical fibers, piezoelectric
the changes in a materials, microelectromechanical
predetermined manner systems (MEMS)

 Actuator –performs a responsive or

adaptive function
Types of actuators

• shape-memory alloys – are metals that after being deformed revert back
their original shape when temp. is changed
• piezoelectric ceramics – expand and contract when exposed to an
electric field; they also generate an electric field when their
dimensions are changed
• magnetostrictive materials – has the same behavior as
piezoelectric ceramics when exposed to a magnetic field
• electrorheological/magnetorheological fluids – experience
changes in viscosity when exposed to electric or magnetic fields
NANOMATERIALS

 The dimensions of this material are in the order of nanometer

(10⁻9 ), even less than 100 nanometers.
 They can be made from any of the four(4) basic types
 Properties of some material change when they approach atomic
dimensions
NANOMATERIALS…
 Nanomaterials find applications in the following:
 Catalytic converters for automobiles
 Nanocarbons: fullerences, nanotubes, graphene
 Particles of carbon black as reinforcement for automobile
tires
 Magnetic nanosize grains that are use for hard disk drives
 etc
End