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Prof. Dr. Yücel BİROL Metallurgical & Materials Engineering
3rd floor / room # 324
Tel: 232 301 74 57
e-mail: [email protected]
lecturer
Fundamentals of Materials Science and Engineering:
An Integrated Approach
3rd Edition
W.D. Callister, Jr. and D. G.
Rethwisch
John Wiley and Sons, Inc.
(2007).
Both book and accompanying
CD-ROM are useful.
textbook
syllabus Come to class! Attendance is encouraged!
if late, don’t panic! Sneak in!
Cell phones silent/off in the classroom!
Be involved in discussions; questions are
welcome! There are no stupid questions,
only stupid people who refuse to ask
them!
Don’t be a stranger; No office hours: drop
by anytime!
Tentative program week # activity
1 / 15.9 What is Materials Science and Engineering?
2 / 22.9 Official holiday
3 / 29.9 Atomic structure of materials
4 / 6.10 Atomic structure of materials; cont’d
5 / 13.10 Crystal structure of materials
6 / 20.10 Crystal structure of materials; cont’d
7 / 27.10 imperfections in solids
Tentative program
week # activity
8 / 3.11 Mid-term
9 / 10.11 diffusion
10 / 17.11 Mechanical properties of materials
11 / 24.11 Mechanical properties; cont’d.
12 / 1.12 Strengthening mechanisms
13 / 8.12 Strengthening mechanisms; cont’d.
14 / 15.12 final
learning objectives
To learn about the microstructural features of
materials and to identify different material groups
based on their microstructural features (week # 1)
To understand the arrangement of atoms in
crystalline structures and to identify the most
closely packed/dense crystal directions and planes
(week # 2-6)
To understand the imperfections in materials and
the role of these imperfections on the deformation
and diffusion processes (week # 7-8)
learning objectives
To learn the transfer and transport mechanisms of
atoms across the materials (week # 9)
To learn about the mechanical properties of
materials and the testing methods employed to
measure these properties (week # 10-11)
To understand the stress-strain curves and to learn
how to estimate the mechanical properties of
materials from these curves (week # 10-11)
learning objectives
To learn the macroscopic and microscopic
characterization techniques employed to identify
material properties (week # ?)
To learn about the basic principals of different
strengthening mechanisms used to improve the
strength of materials (week # 12-13)
To learn about the change in mechanical
properties of materials subjected to deformation
hardening (week # 12-13)
What is materials science? ● study of materials from the macro to the atomic
scale
● with a focus on the effect of structure and
chemistry on material properties!
● from COLA CAN to materials used in AEROSPACE.
● Materials Engineering
(ME) forms a bridge
between the Science
and the Engineering
of materials.
● ME puts theory into
practice in ways that
benefit everybody,
since everything we do
every day involves
materials.
What is materials engineering?
materials science & engineering
● characterize physical and chemical properties of
solid materials so as to enhance inherent
properties, to create or improve end products.
● examine the microstructure to improve the
strength, electrical conductivity, optical or
magnetic properties of a material.
● multidisciplinary, encompassing mechanical,
chemical, biomedical, civil, electrical and
aerospace engineering; physics; and chemistry.
● Materials have historically been important!
different eras of civilization were named after
materials!
● the Stone Age, the Bronze Age, and the Iron Age.
● The development of the semiconductor spawned
the modern era of information technology often
called the Silicon Age.
● Advances in materials science might make this
new millennium biomaterials / nanomaterials /
optical materials age.
Historical perspective
Stone age; The beginning of Material Science!
(2 million years ago!)
People began to make
tools from stone,
Natural materials: stone, wood, clay,
animal skins
The Stone Age ended
about 5000 years ago
with the introduction
of Bronze.
Historical perspective
Paleolithic axe: possibly
>100,000 years old.
Bronze age ( 3000 BC)
a metal made up of Cu + <
25% of Sn + others.
can be hammered or cast into
a variety of shapes, can be
made harder by alloying,
corrodes slowly after a
surface oxide film forms.
Historical perspective
Iron Age began about 3000 years ago (1000 BC)
and continues
today.
Iron and steel,
a stronger and
cheaper
material
made a drastic
impact on the
daily life of a
common person.
Historical perspective
● 2100 AC (throughout the Iron Age)
new materials have been introduced
(ceramic, semiconductors, polymers,
composites!
Historical perspective
Historical Perspective (Cont’d)
Modern Era
Intelligent design of new materials.
Bioinspired materials
Smart materials
Energy materials
Environmentally friendly materials
Why do we study materials?
design problems almost always involve materials
Transportation/aerospace/automotive;
construction/bridges; buildings
We must select the right material from the
thousands available.
understanding the relationship among
processing, structure, properties, and
performance of materials is crucial!
structure subatomic level
Electronic structure of individual
atoms that defines interaction
between atoms (interatomic
bonding)
atomic level
Arrangement of atoms in materials
(the same atoms can have different
properties, e.g. Two forms of
carbon: graphite and diamond)
structure
Micro level (microns)
Arrangement of small grains that
can be identifed with optical
microscopy
Macro level (>mm)
Structural elements that can be
viewed with the naked eye!
Composition
Type of bonding
crystal structure
Processing
define
microstructure
which in turn defines
materials
properties
material properties
ex: hardness vs structure of steel
• Properties depend on structure
ex: structure vs cooling rate of steel
• Processing can change structure
Structure, Processing & Properties H
ard
ne
ss (
BH
N)
Cooling Rate (ºC/s) 100
2 00
3 00
4 00
5 00
6 00
0.01 0.1 1 10 100 1000
(d)
30 mm (c)
4 mm
(b)
30 mm
(a)
30 mm
Property Example (Physics) Properties
Mechanical response to mechanical forces; Rate
of material deformation
Strength
Elastic modulus
Electrical Response of material to an applied
electrical field
Electrical
conductivity
Thermal expansion/contraction with change
in temperature; conduction of heat
and heat capacity
Heat capacity,
thermal
conductivity
Magnetic Response of a material to an applied
magnetic field
Magnetic
susceptibility
Optical absorption, transmission and
scattering of light
Refractive
index
Chemical
stability
Rate of decomposition of material
(often in presence of acid, etc.)
Corrosion rate
Material properties
electrical properties • Electrical Resistivity of Copper:
• Adding “impurity” atoms to Cu increases resistivity.
• Deforming Cu increases resistivity.
T (°C) -200 -100 0
1
2
3
4
5
6 R
esis
tivity,
r (
10
-8 O
hm
-m)
0
thermal properties Space Shuttle Tiles:
Silica fiber insulation
offers low heat conduction!
Composition (wt% Zinc)
Therm
al C
onductivity
(W/m
-K)
400
300
200
100
0 0 10 20 30 40 100 mm
Thermal Conductivity of Cu:
decreases when you add zinc!
magnetic properties
Magnetic Permeability
vs. Composition:
Adding 3% Si
makes Fe a better
recording medium!
Magnetic Storage
Recording medium
is magnetized by
recording head.
Magnetic Field M
ag
ne
tiza
tio
n
Fe+3%Si
Fe
Transmittance:
Aluminum oxide may be transparent, translucent, or
opaque depending on the material structure.
single crystal polycrystal:
low porosity
polycrystal:
high porosity
optical properties
corrosion resistance Stress & Saltwater...
causes cracks!
4 mm material:
7150-T651 Al
"alloy"
(Zn,Cu,Mg,Zr)
Heat treatment: Slows
crack speed in salt water!
held at 160 C
for 1 h
increasing load cra
ck s
peed (
m/s)
“as-is”
10 -10
10 -8
Alloy 7178
selection of materials
Different
materials
have
different
crystal
structures
and
different
properties
aluminium
magnesium
1. Pick Application Determine required Properties
2. Properties Identify candidate Material(s)
3. Material Identify required Processing
Processing: changes structure and overall shape
ex: casting, sintering, vapor deposition, doping
forming, joining, annealing.
Properties: mechanical, electrical, thermal,
magnetic, optical, corrosion.
Material: structure, composition.
Materials Selection Process
Material criteria
Selecting the right material for the job!
final decision has to consider:
In-service conditions that dictate the
material properties
Deterioration of material properties during
service operation.
Overriding criteria: Finished product COST!
In-service conditions
dictates the required
properties
Rarely a material possess
the maximum or ideal
combination of properties
Sacrificing one
characteristic for another
might be necessary
i.e., strength vs. ductility:
the stronger a material the
less ductile (malleable)
Deterioration
Can occur during service operation
Mechanical strength might be lowered by:
Exposure to elevated temperatures
Exposure to corrosive environments
Finished product cost
You could have perfect material, but too costly
Again, some compromise or sacrifice must be
made
Cost of finished piece includes fabrication cost
Metals
Ceramics
Polymers
Classifications are based on:
Chemistry
Atomic Structure
Additional Material Classes:
Composites
Advanced Materials
Material classes
Metals valence electrons detached from atoms – free e-’s!
Long range atomic order
high density
high mechanical strength
very stiff & strong
high ductility
high fracture toughness
high thermal conductivity
high electrical conductivity
typically magnetic
opaque, reflective
Ceramics either positive or negative ions; bound by Coulomb
forces: e-’s tied up! oxides, nitrides & carbides of metallic and
nonmetallic elements Hard & brittle (susceptible to fracture)
low electrical & thermal conductivity/insulators
optically variant
transparent,
translucent or
opaque
Examples:
glass, porcelain
Polymers covalently bonded + weak van der Waals forces
large molecular structures + hydrocarbon chains
decompose at moderate temperatures (100–400C)
lightweight
low strength, soft, ductile
chemical inertness
optically translucent or
transparent
low electrical and
thermal conductivity
examples: plastics,
rubber compounds
Composites composed of materials from two or more classes
Engineered to achieve a combination of properties
not present in one single material
Fiberglass a classic example of a composite
Glass fibers are embedded
within an epoxy or polyester
substrate
Glass fibers: strong & stiff Polymer: ductile & flexible
Composites
BOEING 787 dreamliner
%50 composites!
carbon-fiber composite Ford
Focus hood, weighing 50% less
than a standard steel version.
Future of materials science
Miniaturization
“nanostructured” materials,
with microstructures that has length scales between
1-100 nanometers with unusual properties.
Electronic components, materials for quantum
computing.
Smart/Intelligent Materials
Airplane wings that adjust to the air flow
buildings that stabilize themselves in earthquakes!
Future of materials science
Environmentally friendly materials
Bio/photodegradable plastics
advances in nuclear waste processing
Learning from nature
Shells and biological hard tissue as strong as the
most advanced laboratory-produced ceramics
mollusces produce biocompatible adhesives.
Quantum dots nanocrystal semiconductor materials
small enough to exhibit quantum
mechanical properties.
The electronic properties are intermediate between those
of bulk semiconductors and of discrete molecules.
Applications in transistors, solar cells, LEDs, diode lasers,
medical imaging, quantum computing.
The first commercial release of a product utilizing
quantum dots was the Sony XBR X900A flat panel
television released in 2013.
Typically made of binary compounds such as lead sulfide,
lead selenide, cadmium selenide, cadmium sulfide.
Quantum dots
Colloidal quantum dots
irradiated with a UV light.
Different sized quantum dots
emit different color light due
to quantum confinement.
Sony XBR-55X900A
Ultra high definition TV
Quantum dots in cancer cure
Nanoparticles with intense stable fluoresence to detect tens
to hundreds of cancer biomarkers in blood assays on cancer
tissue biopsies or as contrast agents for medical imaging
Quantum dots in cancer cure
Quantum dots processed with different bio agents to to
detect different types of tumors viewed under UV light.
Quantum dots
are expected to make a very
big impact in cancer cure.
Quantum dots
"Kilosu 10 milyon dolar"
Dünyanın en pahalı yüksek teknoloji ürünü
kuantum dots Türkiye'de üretilecek.
14.9.2014 tarihli
gazete haberi
Carbon nanotubes
Carbon nanotubes are allotropes of carbon with
a cylindrical nanostructure. These
cylindrical carbon molecules have unusual properties, which are
valuable for nanotechnology electronics, optics and other fields
of materials science and technology.
Carbon nanotubes cylindrical structure with a diameter of several nms.
Carbon nanotubes are the strongest and stiffest
materials. This strength results from the covalent
sp2 bonds formed between the individual carbon
atoms. Owing to special
thermal conductivity
and mechanical and
electrical properties,
carbon nanotubes are
additives to various
structural materials in
electronics, optics.
owing to their extraordinary thermal conductivity and mechanical and electrical properties, carbon nanotubes find applications as additives to various structural materials. For instance, nanotubes form a tiny portion of the material(s) in some (primarily carbon fiber) baseball bats, golf clubs, car parts or damascus steel.[2][3]
Carbon nanotubes
owing to their extraordinary thermal
conductivity and mechanical
and electrical properties, carbon nanotubes find
applications as additives to various structural
materials.
nanotubes form a tiny portion of the material(s) in
some (primarily carbon fiber)
baseball bats,
golf clubs,
car parts or
damascus steel.
graphene pure carbon in the form of a one atom thick, nearly
transparent sheet.
a crystalline allotrope of carbon with 2-dimensional
properties.
100 times stronger
than steel!
very low weight
a good conducter
of heat and
electricity.
It was first
produced in the lab in 2004.
graphene Andre Geim and Konstantin Novoselov at the
University of Manchester won the Nobel Prize in
Physics in 2010 "for groundbreaking experiments
regarding the
two-dimensional
material
graphene"
graphene
the main impediment to everyday graphene is the
difficulty and cost associated with manufacturing
the material.
Flexible
computers
could one
day be
made with
graphene
Graphene aerogel
Density: 0.16 mg/cm3.
a lower density than
helium and only twice as
much as hydrogen.
Regular air has a density
of about 1.2 mg/cm3
(7.5 times heavier than
graphene aerogel)
it’s less dense than air,
but this near-magical
substance is still a solid.
Graphene in health care elastic bands with graphene:
a flexible sensor for medical use at reasonable cost.
the highly pliable rubber bands fused with graphene
imparts an electromechanical response on
movement – the material
can be used as a sensor to
measure a patient's
breathing, heart
rate or movement,
alerting doctors to
any irregularities.
Graphene solar panels graphene combined with the transition metal,
dichalcogenides:
so thin and flexible, it can absorb sunlight to
produce electricity at the same rates of solar panels.
the ability to power
homes,
incorporated in
smartphones and
tablets.
Graphene plastic composites as a very stiff, light material, Graphene can be
mixed with epoxy to replace metals within the
automotive and aerospace industry. lightweight cars
and planes?
more fuel
efficient!
for aerospace,
the conductivity
of graphene-
plastic composites
would also help in
electrical storms or interference.
Graphene filters Drinkable Clean Water
researchers have developed a graphene filter.
with tiny holes, this filter keeps salt out, making
saltwater drinkable.
Graphene applications
● gas sensors that can sense down to very low
concentrations—at the parts per trillion level.
● coatings that would make any metal rust-free,
● windows that would darken themselves when the
sun is at its strongest
● anodes for lithium-ion batteries
● Flexible solar cells
● membranes for fuel cells
Nanoengineered textiles
Nanosilver ions are integrated
into the polymer matrix or
coated onto the surface of the
fibres, they offer possibilities
such as improved durability,
self cleaning, and water- or
dirt repellent features.
They protect the wearer
from pathogens, toxic gases,
benefiting the medical and rescue services and
allow the constant monitoring of body functions
Smart Materials Materials science is no longer what it used to be!
We were speaking about passive stuff to be cut,
shaped and formed into components for structures
and machines. We wanted materials that would
survive/degrade as little as possible: that wouldn't
swell, or corrode, or bend, or vibrate.
Now things are different. Many of the advanced
materials at the forefront of materials science are
functional: they are required to do things, to
undergo purposeful change. They play an active
part in the way the structure or device works.
Smart Materials state-of-the-art materials for
new technologies.
these materials are able to
sense changes in their
environments and then
respond to these changes in
predetermined manners.
Components include a type of
sensor and an actuator (that
performs a response).
Smart materials have one or more properties that can be significantly
altered in a controlled fashion by external stimuli,
such as stress, temperature, moisture, pH, electric
or magnetic fields.
Piezoelectric /magnetostrictive materials
Shape memory alloys
PH sensitive polymers
electro/magnetorheological fluids
Halochromic materials
Chromogenic systems
Piezoelectric/magnetostrictive materials Piezoelectric materials are materials that
produce an electric field when stress is applied.
this effect applies also in the reverse manner!
a voltage across the sample will produce stress
and strain within the sample.
Suitably designed structures made from these
materials can therefore be made that bend,
expand or contract when a voltage is applied.
Buzzers are piezoelectric.
Piezoelectric actuators and sensors
Piezoelectric effect (sensor)
An electric field is generated
due to a change in dimensions
of a material
+
-
-
+
Converse Piezoelectric effect (actuator)
A change in
dimensions of
a material due to
an electric field
Piezoelectric materials sensors which deploy car airbags.
The material changes in shape with the impact thus
generating a field which deploys the airbag.
Piezoelectric materials
Car electric lighters use
piezoelectric materials:
A spark is created by
pressing a button that
compresses a
piezoelectric crystal
(piezo ignition),
generating an electric
arc.
Use of piezo-electric
ceramics in active
damping mechanisms
to reduce vibrations
application of a
current / voltage
results in mechanical
deflection … or vice
versa
Piezoelectric ceramics
magnetostrictive materials
similar to piezoelectric except for magnetic fields.
Magnetostrictive materials can convert magnetic
energy into kinetic energy, or the reverse, and are
used to build actuators and sensors.
Automotive suspensions
Automotive steering
Automotive tank levels
magnetostrictive materials a linear electromagnetic motor at each wheel.
There are magnets and coils of wire inside the
motor. When electrical power is applied to the
coils, the motor retracts and extends, creating
motion between the wheel and car body.
shape memory alloys (SMA)
Shape memory alloys are thermoresponsive
materials – after being deformed, revert back to
their original shape with a temperature change.
One of the most common alloys is a combination
of nickel and titanium.
This shape memory alloy can be treated so that
when it reaches a set temperature it contracts.
When it cools it then returns to its original
shape.
Application of SMA Nitinol is used in medicine for stents:
A collapsed stent can be inserted into a vein and
heated (returning to its original expanded shape)
helping to improve blood flow.
Also, as a replacement
for sutures where nitinol
wire can be weaved through
two structures then allowed
to transform into it's
pre-formed shape which
should hold the structures
in place.
Shape memory alloy wire remembers its shape.
When a small electrical
current passes through
the wire, it changes
shape.
The wire becomes shorter.
This shortening can be
used to control a robotic
hand.
Shape memory alloys
In the future, this may help to produce artificial
motion that similar to the human movement.
Shape memory alloys are alternatives to conventional
steel and concrete in bridges.
They endure heavy strain and still return to their
original state, either through heating or
superelasticity. SMAs demonstrate an ability to re-
center bridge columns,
which minimizes the
permanent tilt columns
can experience after an
earthquake.
Shape memory alloys in civil engineering
PH sensitive polymers pH-sensitive polymers are materials which
swell/collapse when the pH of the surrounding
media changes.
The sensor is prepared by entrapping within a
polymer matrix a pH sensitive dye that responds,
through visible colour changes
two kinds of pH sensitive materials: one which
have acidic group and swell in basic pH, and others
which have basic groups and swell in acidic pH.
Polyacrylic acid is an example of the former and
Chitosan is an example of the latter.
Drug release systems
Controlled release of insulin
Hydrogel works as insulin containing reservoir
within copolymer in which glucose oxidase is
immobilized.
molecular entraces for delivery of insulin
protons are released causing the gates to be
opened for transportation of insulin.
electrorheological fluids
The particles are randomly
distributed in a low strength
field. They align with an
increase in the viscosity of
the fluid when a higher field
strength is applied.
The viscosity changes
X 100,000 in response to an electric field.
suspensions of extremely fine
non-conducting particles in an
electrically insulating fluid.
A simple ER fluid can be made by
mixing cornflour in a light
vegetable oil or silicone oil/cross
linked polyurethane particles in
silicone oil.
The particles are 5 microns in
diameter and contain dissolved
metal ions for fast polarisation and
the electro rheological effect.
Electrorheological fluids
Electrorheological fluids valves and clutches: when the
electric field is applied, an ER
hydraulic valve is shut or the
plates of a
clutch are
locked
together, when
the electric
field is removed
the ER hydraulic
valve is open or
the clutch plates are disengaged.
Used in hydraulic
Electrorheological fluids
Used in the automotive and aerospace industries in
vibration damping and variable torque transmission.
smooth ride and steering
Magnetorheological materials
Magnetorheological fluid is a type of smart
material that has the ability to change state when
placed in a magnetic field.
These fluids are composed of iron-
like particles.
In their normal state they are fluid.
When placed in a magnetic field
the particles are attracted to each
other and join up to form a solid.
MR dampers are used to control the suspension in
cars to allow the feel of the ride to be varied.
Mercedes cars: electronic air suspension!!
Magnetorheological materials
Dampers are also
used in prosthetic
limbs to allow the
patient to adapt to
various
movements for
example the
change from
running to
walking.
Magnetorheological materials
Halochromic Materials
Halochromic materials are
materials that change
their colour as a
result of changing
acidity.
One suggested
application is for paints
that can change colour to
indicate corrosion in the
metal underneath them.
Chromogenic systems
change colour in response to electrical,
thermal or optical changes.
electrochromic materials
thermochromic materials
photochromic materials
Chromogenic materials
Electrochromic materials
Flip a switch and an electrochromic
window can change from clear to
fully darkened or any level of tint
in-between.
The windows operate on a very low
voltage and only use energy to
change their condition, not to
maintain any particular state.
Thermochromic materials Thermochromic materials react to changes in
temperature: temporarily change colour when they
are exposed to heat.
● Tiny capsules in thermochromic
ink contain liquid crystals.
● As the temperature changes
these crystals move.
● The reorientation of the
crystals changes how the
material reflects light,
with a change in colour!
Thermochromic materials Kettles that change colour and signs that
glow-in-the-dark.
thermochromic pigments are now routinely
made as inks for paper and fabrics – and
incorporated into injection moulded plastics.
Warm Cool
Thermochromic materials
The pigments can be incorporated in to dyes for
fabric to produce clothing
which changes colour
with temperature.
Thermochromic inks can
also be used for printing
on to clothing and food
packaging.
‘Smart’ clothing for heat release / retention
Photochromic materials Photochromic materials are sensitive to light:
undergo a reversible change of colour when exposed
to a certain amount of light.
Photochromic lenses become
dark when they are exposed
to UV radiation.
Once the UV radiation is
removed, the lenses gradually
return to their normal state.
They can be made
of either glass or plastic.
Biologically inspired materials Animals show an impressive
performance in classifying, localizing and tracking odor trails.
Dogs can track scent trails of a particular person and identify buried land mines.
Moths can use single-molecule hits of scent to locate the female.
Simple insects use wind sensors and chemical sensors.
Biologically inspired materials
Bioinspired materials are synthetic materials whose
structure, properties mimic those of natural
materials or organisms. Examples of bioinspired
materials are light-harvesting photonic materials
that mimic
Photosynthesis!
Hair bundles in the
inner ear that transduce
mechanical motion into
electrical signals
Polymer E-nose Technology Polymer doped with conducting particles.
polymer swells upon exposure to odor.
longer path for current, hence higher resistance.
Conduction mechanism primarily electron tunneling.
Resis
tan
ce
e- e-
A
B On Off
Time
insulating polymer matrix
conducting element
Polymer E-nose Technology
capable of detecting most
Toxic Industrial Chemicals
(TICS) and Chemical
Warfare Agents (CWA) -
such as Sarin, at levels
below IDLH (Imminent
danger to life and health).
Nanoengineered Materials atoms are arranged bottom up to develop
mechanical, electrical, magnetic, and other
properties into materials that are otherwise not
possible.
‘Nano’: on the order of a nanometer, or 10-9 m.
Self cleaning paints car that can clean itself instantly using a special
kind of paint.
The ultra resistant paint uses nanotechnology
to create a thin air shield
above the surface of the
car that makes rain, road
spray, frost, sleet and
standing water roll off
the car without tainting
its surface at all.
Repels water and oils,
as well as dirt, dust, mud and grit
multiferroics Certain metal oxides, can
exhibit both magnetism
and ferroelectricity. An
electric field will alter the
magnetic state, and a
magnetic field can alter
the electrical polarization.
This allows us to store
data using an electric
field, which is much easier
to generate than a
magnetic field.
Advanced materials
Newly developed, high
performance materials
high-tech applications
semiconductors,
biomaterials, materials in
lasers, integrated circuits,
magnetic storage, LCD’s, and
fiber optics.
Semiconductors Semiconductors have electrical properties that are
intermediate between the electrical conductors
(metals and alloys) and insulators (ceramics and
polymers).
electrical properties
depend strongly on
minute proportions of
contaminants.
Examples: Si, Ge, GaAs.
Semiconductors Semiconductors have made possible the advent of
integrated circuitry that has revolutionized electronics and the computer industry.
Light emitting diodes
LED is a special semiconductor that illuminates
When an electrical charge passes through it. LEDs
Are commonly green, amber or red; however can be
An assortment of other
colors.
amoled AMOLED (active-matrix organic
light-emitting diode) is a display
technology for use in mobile
devices and televisions.
OLED describes a specific type of thin
film-display technology in which
organic compounds form the
Electroluminescent material, and
active matrix refers to the
Technology behind the addressing of
pixels.
AMOLED technology is used in mobile
phones, media players and digital cameras.
Biomaterials implanted into the human body for replacement
of diseased/damaged body parts
must not produce toxic substances and must be
compatible with body tissues.
Metals, ceramics,
polymers,
composites,
semiconductors
may all be used as
biomaterials.
Hip Implant
Requirements
mechanical strength (many cycles)
good lubricity
biocompatibility
With age or certain illnesses joints deteriorate.
Particularly those with large loads (such as hip).
Optical lenses Silicone & Hydrogel Contact Lenses
difference between silicone hydrogel lenses and
conventional hydrogel lenses is the high oxygen
transmissibility of silicone hydrogel lenses.
Conventional hydrogel lenses are classified
according to the water content. Low hydrogels
range between 12-30%
water; high hydrogels
range from 90-99.5%
water content.
Ceramic cement for bone repair
Frontal views 6 months after reconstruction of
full-thickness defect with hydroxyapatite bone
paste (Bone Source)
Advanced materials in sports change in racket frames
from wood to aluminium
then to fibre reinforced
composites has resulted in
larger racket heads. An
increase in the sweet-spot
area on the racket face
means the ‘power’ of the
racket has increased, which
has increased the speed of
the game.
The serve speed has increased
to 155 mph.
Spectators have complained
about the lack of rallies and
excitement in the game.
To slow the game down on fast
surfaces new balls are being
introduced. One new ball type
is 6% larger giving a 12%
increase in drag and hence 10%
increase in response time for
the receiver.
Advanced materials in sports
Solar Cells/photovoltaics ● Photons in sunlight hit the solar panel and
are absorbed by semiconducting materials,
such as silicon.
● Electrons (negatively charged)
are knocked loose from their
atoms, allowing them to flow
through the material to
produce electricity.
● An array of solar cells
converts solar energy
into DC electricity.
Nellis AFB Solar panels
Future of photovoltaics Convergence of PV and nanotechnology to capture
and convert solar energy more efficiently
Inexpensive plastic solar cells or panels that are
mounted on curved surfaces
nanotubes, flexible plastic organic transparent
cells, ultra-thin silicon wafers
Fuel Cells ● Fuel cells are like batteries
● We feed hydrogen gas into one side.
● hydrogen is split into hydrogen ions and
electrons.
● Only H+ can transfer through the cell through
the electrolyte.
● Electron transfer produces electricity!
● H+ ions and electrons combine with oxygen from
the air and make water at the other electrode.
Fuel Cells
H2
H2
H2
O2
O2
O2
H+
H+
H+
H+
H+
e-
e-
e-
e-
e- e-
e-
e-
e-
e-
H2 2H+ + 2e- ½ O2 + 2e- + 2H+ H2O
hydrogen to fuel a car?
Unlike batteries, fuel cells don’t need to be
replaced. We just
have to refill
the tank with H2!
aerogels
porous, solid materials that exhibit extreme
materials properties.
known for their extreme low densities (0.0011 to
~0.5 g cm-3).
a silica aerogel is only three times heavier than
air.
Typically aerogels are 95-99% air (or other gas) in
volume, with the lowest-density aerogel ever
produced being 99.98% air in volume.
●
●
●
●
aerogels – frozen smoke made of Silica with the sol-
gel process.
a gel is created in solution
and then the liquid is
removed.
Aerogels are good thermal
insulators.
hydrogels for tissue engineering
Hydrogels are formed by
crosslinking polymer
chains, through physical,
ionic or covalent
interactions, and are
well known for their
ability to absorb water.
biological substitutes that
restore, maintain, or
improve tissue function
Materials in wind power Materials play a critical role in wind power.
wind turbines use blades made of polymer-matrix
composite materials reinforced with Fiber glass
or graphite fibers.
Compact electrical generators in the turbines
contain powerful magnets made from rare earth
materials.
The rotation of the turbine blades is used to drive
an electrical generator through a gearbox, which
uses special alloys in order to accommodate a wide
range of wind speeds.
Materials in wind power
Turbine sizes continue to increase.
The growth of off-shore installations means long-
time exposure to higher stresses and hostile
environments that can challenge the durability of
turbine materials.
The turbine blades must have adequate stiffness to
prevent failure due to deflection and buckling.
They also need adequate long term fatigue life in
harsh conditions, including variable winds, ice
loading and lightning strikes.
Materials in wind power
Smart blade materials that automatically
adjust pitch to accommodate wind speed
variations for the most efficient operation
will high strength materials that resist
corrosion and fatigue
Sensors included
in turbine blades to
continuously monitor
fatigue damage and
signal the need for repair
Transportation
● Continued reductions in vehicle mass can be
achieved through
● Advanced High Strength Sheet Steels (AHSS)
developed to enable low-cost crash-resistant
vehicle manufactured with reduced
● sheet thickness and vehicle weight
● light metal developments and application of
new aluminum, magnesium, titanium alloys.
Transportation ● Carbon fiber composites may also play an
increasing role, especially where the weight
savings can justify the much greater cost
● New materials developments to enhance energy
storage (advanced batteries) and conversion
● Advanced magnetic materials and electric
motors
● Membranes and catalysts for fuel cells
● Structural materials for high power-density
drive trains
Energy efficient buildings
● net-zero energy balance buildings:
● lower cost multifunctional materials
● more efficient solid state lighting materials
● more corrosion resistant metals
● improved manufacturing processes
Energy efficient buildings
● Materials have increased the energy efficiency
of today’s buildings
● Low emissivity glass, significantly lowering the
initial investment costs for heating and cooling
● Compact fluorescent lighting and light emitting
diodes (LEDs), reducing lighting costs and heat
loads
● Cool roofs, saving energy
● High efficiency fiber glass insulation
Energy efficient buildings ● Phase change materials to store or
release large amounts of energy in the
walls, floor and roof, thereby saving
energy
● inorganic nanomaterials to positively
influence the solar gain and provide
long term durability
● Electrochromic and liquid crystal
glasses responding to occupants and
external conditions to actively control
both light and solar gain
Phase change materials phase-change material is a substance with a high
heat of fusion which, melting and solidifying at a
certain temperature, is capable of storing and
releasing large amounts of energy. Heat is absorbed
or released when
the material
changes from solid
to liquid and vice
versa.
A sodium acetate heating pad.
When the sodium acetate solution
crystallises, it becomes warm.
Energy storage and transmission
● Energy storage solutions require short-term as
well as long-term high capacity storage methods
and materials
● Supercapacitors—carbon nanotube or other
electrode materials with high internal surface
area, high polar electrolytes
● Batteries—deep discharge and high cycle
materials (lithium-based batteries, lead acid
with new electrodes, flow batteries)
● Sunlight is an important carbon-neutral energy
source.
● More energy from sunlight strikes the Earth in one
hour (13 terawatts) than all the energy consumed
by humans in one year. (0.02% of the total
electrical power is from solar energy.)
● Materials scientists and engineers can provide
materials-based solutions to efficiently capture
the unlimited and free energy from sunlight to
address the world’s energy needs.
Future needs-energy issues
● light battery materials with storage capacity
● turbine blades that can operate at 2500 C
● room temperature super conductors,
● chemical sensors (artificial nose)
● Corrosion-resistant alloys for
high-temperature
power conversion
Future needs-energy issues
Hydrogen fuel cell very feasible and attractive
Holds promise in the car industry as a power source
For this to be efficient,
better materials must
be engineered
Future needs-energy issues
Many materials used are from non-renewable
sources
i.e. oil and some metals
Materials are being depleted steadily which is
cause for:
Need of discovery of additional reserves
Development of similar materials with less
adverse environmental impact
Increase recycling efforts
Future materials needs