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The Fundamentals of Materials Science
An Introduction to Materials Science
School of Materials Science and Engineering
Shengjuan Li
Email:[email protected]
School of Materials Science and Engineering
A broad survey of materials, their properties,
and the origin of their properties.
Toe pad of a gecko
Performance: Extraordinary adhesion
Self-cleaning adhesive
Mechanism of adhesion
Microscopically small hairs
Van der Waals forces
Properties
Mechanical, optic….
An interesting bionics
B Chen, P.DWu, H Gao. Hierarchical modelling of attachment and detachment mechanisms of
gecko toe adhesion. Proc. R. Soc. A (2008) 464, 1639–1652. DOI: 10.1098/rspa.2007.03
interdisciplinary questions
Materials- - - Applications Mikoyan-Gurevich MiG-25 （Foxbat）
supersonic interceptor(拦截机） and
reconnaissance aircraft（侦察机）
High-speed (2.8, 3.2 Mach), high-altitude
Stainless steel
Merits：heat resistance, cheap
Faults: too heavy
North American XB-70 (Valkyrie)
nuclear-armed, deep-penetration strategic
bomber
High-speed (3.1 Mach), high-altitude
stainless steel, sandwiched honey comb panels,
and titanium
Merits：heat resistance, expensive, light weight
About this course:
Course Objective
Introduce fundamentals (theory and concepts) in Materials
Science
You will learn about:
material structure
how structure dictates properties
how processing can change structure
This course will help you to:
use materials properly
realize new design opportunities with materials
School of Materials Science and Engineering
Course materials: As a reference book, “Materials Science and Engineering”
by Callister and Rethwisch is recommended, but not required.
The outlines of lectures will be provided on the course website
prior to the date of the lecture.
Likewise, reference and reading materials, and assignments will
also be posted on the course website.
Optional Material:
Chapter 1 - Introduction What is materials science?
Why should we know about it?
Materials drive our society
Stone Age-silicate
Bronze Age-copper alloy
Iron Age-ferroalloy
Now? Silicon Age?
Polymer Age?
Carbon Age?
Graphene Age?
Zax, Quadripod, Iron hoe , Swords
“stuff” and its characterization Materials science involves investigating the relationships that
exist between the structures and properties of materials.
In contrast, materials engineering is, on the basis of these
structure‐property correlations, designing or engineering thestructure of a material to produce a predetermined set of
properties.
From a functional perspective, the role of a materials
scientist is to develop or synthesize new materials.
A materials engineer is called upon to create new products
or systems using existing materials, and/or to develop
techniques for processing materials.
School of Materials Science and Engineering
structure
single-walled
multi-walled
3D architectured
....
property
strength
hardness
Electrical properties
...
relationship
.... new products, processing
Fig. 3 Schematic diagram of apparatus for preparing CNTs
by chemical vapor deposition(CVD)
1-gas mixing; 2-catalysts; 3-power source; 4-quartz tube;
5-temperature control; 6-thermocouples
new materials
Application of the tetrahedron of MSE in the automotive industry.
Note: the microstructure-synthesis and processing-composition are all interconnected and affect the performance-to-cost ratio.
“Compositions”
Copper alloy (high resistance against corrosion)
(Brass(Zn), Bronze, Nickel silver, Cupronickel…)
Cu –high melting point (Tm), 1083℃，excellent ductility (deformability);
Sn (Stannum ,Tin) – low melting point, 232℃
Bronze(Ti): 85% Cu，15% Sn, Tm 960℃，ductility ，hardness ，good luster
“Structure” Macro structures
Micro structures
School of Materials Science and Engineering
Range Dimension
macroscopy ～1026m
mesoscopy 1nm～100nm
microscopy ～10-15m
Internal structures
Atomic
structures
Interatomic
bonding
Microscopic
structures
Atomic
arrangement
Processing
Rolling Casting
a)Rolling b)extruding c)drawing d) free forging e)die forging f)sheet stamping
“Property”
While in service use, all materials are exposed to external
stimuli that evoke some type of response.
For example, a specimen subjected to forces will experience
deformation, or a polished metal surface will reflect light. A
property is a material trait in terms of the kind and
magnitude of response to a specific imposed stimulus.
Generally, definitions of properties are made independent of
material shape and size.
School of Materials Science and Engineering
Oxygen
Zinc
Properties of solid materials Mechanical
Mechanical properties relate deformation to an applied load or force; examples include elastic modulus and strength.
Electrical
Electrical conductivity and dielectric constant, the stimulus is an electric field.
Thermal
Heat capacity and thermal conductivity
Magnetic
Response to the application of a magnetic field,magnetic conductivity
Optical
index of refraction and reflectivity. The stimulus is electromagnetic or light radiation
Deteriorative
Relate to the chemical reactivity of materials
“Property” While in service use, all materials are exposed to external
stimuli that evoke some type of response.
For example, a specimen subjected to forces will experience
deformation, or a polished metal surface will reflect light. A
property is a material trait in terms of the kind and
magnitude of response to a specific imposed stimulus.
Generally, definitions of properties are made independent of
material shape and size.
Oxygen
Zinc
School of Materials Science and Engineering
Mechanical
Representative strengths of various categories of materials
School of Materials Science and Engineering
MechanicalDeformation to an applied
load or force: elasticmodulus and strength.
Mechanical
The stress of low carbon steel with the grain size
School of Materials Science and Engineering
Electrical ElectricalElectrical conductivity and
dielectric constant, thestimulus is an electricfield.
22
Thermal• Space Shuttle Tiles:
-- Silica fiber insulation
offers low heat conduction.
• Thermal Conductivity
of Copper:
-- It decreases when
you add zinc!
Adapted from
Fig. 19.4W, Callister 6e.
(Courtesy of Lockheed
Aerospace Ceramics
Systems, Sunnyvale, CA)
(Note: "W" denotes fig.
is on CD-ROM.)
Adapted from Fig. 19.4, Callister & Rethwisch 8e.
(Fig. 19.4 is adapted from Metals Handbook:
Properties and Selection: Nonferrous alloys and
Pure Metals, Vol. 2, 9th ed., H. Baker, (Managing
Editor), American Society for Metals, 1979, p.
315.)
Composition (wt% Zinc)T
her
mal
Con
du
ctiv
ity
(W
/m-K
)
400
300
200
100
00 10 20 30 40
100mm
Adapted from chapter-
opening photograph,
Chapter 17, Callister &
Rethwisch 3e. (Courtesy
of Lockheed
Missiles and Space
Company, Inc.)
ThermalHeat capacity and thermal
conductivity
23
Magnetic• Magnetic Permeability
vs. Composition:-- Adding 3 atomic % Si makes Fe a
better recording medium!
Adapted from C.R. Barrett, W.D. Nix, and
A.S. Tetelman, The Principles of
Engineering Materials, Fig. 1-7(a), p. 9,
1973. Electronically reproduced
by permission of Pearson Education, Inc.,
Upper Saddle River, New Jersey.
Fig. 20.23, Callister & Rethwisch 8e.
• Magnetic Storage:-- Recording medium is
magnetized by recording head.
Magnetic Field
Magn
etiz
ati
on Fe+3%Si
Fe
MagneticResponse to the application of a magnetic
field, magnetic conductivity.
• Transmittance: -- Aluminum oxide may be transparent, translucent, or
opaque depending on the material structure.
Adapted from Fig. 1.2,
Callister & Rethwisch 8e.
(Specimen preparation,
P.A. Lessing; photo by S.
Tanner.)
single crystal
polycrystal:
low porosity
polycrystal:
high porosity
Optical
OpticalIndex of refraction and reflectivity.
The stimulus is electromagnetic or light radiation
25
Deteriorative• Stress & Saltwater...
-- causes cracks!
Adapted from chapter-opening photograph,
Chapter 16, Callister & Rethwisch 3e.
(from Marine Corrosion, Causes, and Prevention,
John Wiley and Sons, Inc., 1975.)
4mm-- material:
7150-T651 Al "alloy"
(Zn,Cu,Mg,Zr)
Adapted from Fig. 11.26,
Callister & Rethwisch 8e. (Provided courtesy of G.H.
Narayanan and A.G. Miller, Boeing Commercial Airplane
Company.)
• Heat treatment:
-- slows crack speed in salt water!
Adapted from Fig. 11.20(b), R.W. Hertzberg, "Deformation and
Fracture Mechanics of Engineering Materials" (4th ed.), p. 505, John
Wiley and Sons, 1996. (Original source: Markus O. Speidel, Brown
Boveri Co.)
“held at
160ºC for 1 hr
before testing”
increasing loadcra
ck s
pee
d (
m/s
)
“as-is”
10 -10
10-8
Alloy 7178 tested in
saturated aqueous NaCl
solution at 23ºC
DeteriorativeRelate to the chemical
reactivity of materials
26
Example – Hip Implant 髋关节植入物
With age or certain illnesses joints deteriorate. Particularly those
with large loads (such as hip).
Adapted from Fig. 22.25, Callister 7e.
Example – Hip Implant
Requirements
mechanical strength
(many cycles)
good lubricity
biocompatibility
Adapted from Fig. 22.24, Callister 7e.
骨盆 脊柱
髋臼，关节窝
股骨
The goal is clear:
specific objective
28
Example – Hip Implant
Adapted from Fig. 22.26, Callister 7e.
髋假体
固着剂
骨盆
股骨柄
股骨
29
Hip Implant
Key problems to overcome
fixation agent to hold
acetabular cup
cup lubrication material
femoral stem – fixing agent (“glue”)
must avoid any debris in cup
Femoral Stem
Ball
Acetabular
Cup and Liner
Adapted from chapter-opening photograph,
Chapter 22, Callister 7e.
股骨柄
30
ex: hardness vs structure of steel
• Properties depend on structure
Data obtained from Figs. 10.30(a)
and 10.32 with 4 wt% C composition,
and from Fig. 11.14 and associated
discussion, Callister & Rethwisch 8e.
Micrographs adapted from (a) Fig.
10.19; (b) Fig. 9.30;(c) Fig. 10.33;
and (d) Fig. 10.21, Callister & Rethwisch
8e.
ex: structure vs cooling rate of steel
• Processing can change structure
Structure, Processing & Properties
Hard
nes
s (B
HN
)
Cooling Rate (ºC/s)
100
200
300
400
500
600
0.01 0.1 1 10 100 1000
(d)
30mm(c)
4mm
(b)
30mm
(a)
30mm
Application of the tetrahedron of MSE in the automotive industry.
Note: the microstructure-synthesis and processing-composition are
all interconnected and affect the performance-to-cost ratio.
MiG-25
XB-70
Why do we study materials science?
Many an applied scientist or engineer, whether mechanical,
civil, chemical, or electrical, will at one time or another be
exposed to a design problem involving materials. Examples
might include a transmission gear, the superstructure for a
building, an oil refinery component, or an integrated circuit
chip.
Of course, materials scientists and engineers are specialists
who are totally involved in the investigation and design of
materials.
School of Materials Science and Engineering
Types of Materials
CompositesComposed of two (or more) individual materials (metals, ceramics, and
polymers).
A combination of properties: by any single material, and also to
incorporate the best characteristics of each of the component materials.
Some naturally-occurring composites: wood and bone. Synthetic (or man-
made) composites.
Fiberglass– small glass fibers are embedded
within a polymeric material (normally an epoxy
or polyester. Property: strong and stiff (but also
brittle), flexible, and ductile. has a low density.
Carbon fiber reinforced polymer (or “CFRP”) composite—
carbon fibers that are embedded within a polymer.
Properties: stiffer and stronger , more expensive.
used in some aircraft and aerospace applications, as well as high-tech
sporting equipment (e.g., bicycles, golf clubs, tennis rackets, and
skis/snowboards).
环氧树脂
涤纶
Figure 1.3 Bar-chart of room temperature density values for various
metals, ceramics, polymers, and composite materials.
XB-70
Figure 1.4 Bar-chart of room temperature stiffness (i.e., elastic modulus)
values for various metals, ceramics, polymers, and composite materials.
MiG-25
Figure 1.5 Bar-chart of room temperature strength (i.e., tensile strength)
values for various metals, ceramics, polymers, and composite materials.
Figure 1.6 Bar-chart of room-temperature resistance to fracture (i.e., fracture
toughness) for various metals, ceramics, polymers, and composite materials.
(Reprinted from Engineering Materials 1: An Introduction to Properties,
Applications and Design, third edition, M. F. Ashby and D. R. H. Jones, pages
177 and 178, Copyright 2005, with permission from Elsevier.)
断裂韧性
Figure 1.7 Bar-chart of room temperature electrical conductivity ranges
for metals, ceramics, polymers, and semiconducting materials.
References
http://mse.ustb.edu.cn/jiaoyujiaoxue/jingpinkecheng/
Advanced materialsMaterials that are utilized in high-technology (or high-tech) applications are
sometimes termed advanced materials.
Application:
electronic equipment, computers, fiber-optic systems, spacecraft, aircraft, and
military rocketry.
Advanced materials include semiconductors, biomaterials, and what we may
term “materials of the future” (that is, smart materials and nano-engineered
materials), which we discuss below. The properties and applications of a
number of these advanced materials—
for example, materials that are used for
lasers, integrated circuits, magnetic
information storage, liquid crystal displays
(LCDs), and fiber optics.
光纤
Troditional materials with enhanced
properties ， new-developed ， high-performance.
Materials of the Future
Smart Materials
Smart (or intelligent) materials are a group of new and state-of-the-art
materials now being developed that will have a significant influence on
many of our technologies.
The adjective “smart” implies that these materials are able to sense
changes in their environments and then respond to these changes in
predetermined manners—traits that are also found in living organisms. In
addition, this “smart” concept is being extended to rather sophisticated
systems that consist of both smart and traditional materials.
Smart Materials Components of a smart material (or system) include some
type of sensor (that detects an input signal), and an
actuator (that performs a responsive and adaptive
function).
Actuators may be called upon to change shape, position,
natural frequency, or mechanical characteristics in
response to changes in temperature, electric fields,
and/or magnetic fields.
Four types of materials are commonly used for actuators:
shape memory alloys,记忆合金
piezoelectric ceramics, 压电陶瓷
magnetostrictive materials, 磁致伸缩材料
electrorheological/magnetorheological fluids. 电流变/磁流变液
制动器
固有频率
Piezoelectric ceramics
Various aspect ratios of ZnO nanotubes created for this research, where higher
ratios had greater efficiencies (Photo: Professor James Durrant)
46
Nanoengineered Materials “top-down” and “bottom-up” approach.
With the advent of scanning probe microscopes, which permit
observation of individual atoms and molecules, it has become
possible to manipulate and move atoms and molecules to form
new structures and, thus, design new materials that are built from
simple atomic-level constituents (i.e., “materials by design”).
One example of a material of this type is the carbon nanotube. In
the future we will undoubtedly find that increasingly more of our
technological advances will utilize these nanoengineered materials.
Selecting the right material
Several criteria:
First of all, the in-service conditions must be characterized,
A second selection consideration is any deterioration of
material properties that may occur during service operation.
Finally, probably the overriding consideration is that of
economics: What will the finished product cost? A material may
be found that has the ideal set of properties but is prohibitively
expensive. The cost of a finished piece also includes any
expense incurred during fabrication to produce the desired
shape.
School of Materials Science and Engineering
50
1. Pick Application Determine required Properties
Processing: changes structure and overall shape
ex: casting, sintering, vapor deposition, doping
forming, joining, annealing.
Properties: mechanical, electrical, thermal,
magnetic, optical, deteriorative.
Material: structure, composition.
2. Properties Identify candidate Material(s)
3. Material Identify required Processing
The Materials Selection Process
51
1. Clear design goal Determine required Properties
4. When the goal changed, should update the solution.
Avoid “Nick the boat to seek the sword”.
2. The difference between the engineer and science,
No definitely right answer
3. Some problems are solved, new problem derived.
What is a good product?
SUMMARY
School of Materials Science and Engineering
• Use the right material for the job.
• Understand the relation between properties,
structure, and processing.
• Recognize new design opportunities offered
by materials selection.
Course Goals:
SUMMARY
School of Materials Science and Engineering
• mechanical, electrical, thermal, magnetic,
optical, deteriorative.
• components; subatomic, atomic, microscopic and
macroscopic structure.
• processing, structure, properties, and performance.
(1) Six different property classification of materials:
(2) Relationship between structures and properties:
(3) Four elements to consider:
(4) Three important criteria in materials selection:
• in-service conditions, deterioration of material properties,
economics or cost.
Lecturer: Shengjuan Li
Location:
The course is now scheduled for Room 344 in First
Teaching Building
Office: Room 201 in School of MSE
Office time：Mondays, 15：00-17：00
Mondays, Thursdays 18：00-20：00
Time: Mondays (3,4,5), Wednesdays (3,4,5)
School of Materials Science and Engineering
Lectures
A broad survey of materials, their properties,
and the origin of their properties.
That’s all for
today, thanks!
Behind every beautiful thing, there's some kind of pain.
