Introduction to
Materials Science and
Engineering
Guan Rui-fang
材料与新技术革命
材料与国防现代化
? This book is divided into four
major sections
I,The fundamentals
II,The structural materials
III,The electronic and magnetic
materials
IV,Materials in engineering design
science
materials
engineering
? Nature of materials’
properties
? Microscopic or
submicroscopic
structure
? Engineering
design
Chapter I
Materials for Engineering
1.1 Types of materials
1.2 From structure to properties
1.3 Selection of materials
1.4 Materials science and
engineering
Key word
? Alloy [5AlCi]
? Atomic-scale-architecture
? Brittle [5britl]
? Ceramic [si5rAmik]
? Composite [5kCmpEzit,-
zait]
? Concrete [5kCnkri:t]
? Conductor
? Crystalline [5kristElain] adj.
? Devitrified [di:5vitrifai]
? Ductility [dQk5tiliti]
? Electronic and magnetic material
? Element [5elimEnt]
? Fiberglass [5faIbE^lB:s]
? Glass
? Glass-ceramic
? Insulator
? Materials science and engineering
? Materials selection
? Metallic
? Microcircuitry
[5maIkrEJs\:kIt]
? Microscopic-scale architecture
? Noncrystalline
? Nonmetallic [5nCnmi5tAlik]
Key word
? Oxide
? Periodic[piEri5Cdik]
table
? Plastic
? Polyethylene
[7pCli5eWili:n]
? Polymer
? Property
? Refractory
? Semiconductor
? Silica硅石,SiO2
? Silicate]硅酸盐
? Silicon硅元素
? Steel
? Structural material
? wood
Key word
1.1 Types of materials
? a, Metals metallic bond
? b, Ceramics (glass) ionic [aI5RnIk]
and covalent [kEu5veilEnt] bond
? c, Polymers covalent and Van der waals
bond
? d, Composites
? e, semiconductors
What materials are available to me?
Five categories
A Metals
超塑性的,超塑性材料 (制 )的
1, i.e.
Latin,the written abbreviation for id est,
也就是，即。 读作,that is
2, state-of-the-art
技术发展水平，现代化的。
3, superplastic.
? Characteristics(metallic 金属的，金属性的 )
? It is strong and can be readily formed into
practical shapes,
? Ductile [5dQktail] — permanent
deformability
? metallic luster
? electric conductor
Metals have no brittleness and are safe for
many applications.
Structural steel
Gasket
[5^Ask
it]
垫圈,衬垫
spring wire
Valve [vAlv]
B Ceramics [si5rAmiks]
A homogeneous mixture of two or more substances,
which may be solids,liquids,gases,or a combination of
these,
1, Refractory [ri5frAktEri]
Difficult to melt or work; resistant to heat.
2, fracture toughness 断裂韧度
3, crystalline[5kristElain]
Being,relating to,or composed of crystal or crystals.
4, Devitrify [di:5vitrifai]
To cause (a glassy material) to become crystalline and
brittle.
5, solution
? The ceramics is derived from
Greek word,keramic” which
means an art of potter,
Include,
? glass ; enamels [i5nAmEl] ;
refractories ; cements ;
? limes ; plasters(plaster of Paris) ;
cermets[5sE:met]金属陶瓷,含陶合金 ;
? electronic ceramics ;
? high and low tension electrical
insulators ;
? structural clay products ; nuclear
ceramics ;
? whitewares ; abrasives [E5breisiv],
The Different Colors of
Corundum [kE5rQndEm]
Ruby
Sapphire
[5sAfaiE]
Why shouldn’t Al2O3 be chosen for
certain applications where metallic
aluminum has been used?
1,Al2O3 have two advantages:
first,chemically stable ;
Al oxidized
second,higher melting point (20200C)
Al (6600C)
refractory
use in industrial furnace
construction
Questions
1,What materials are available to you in
this book?
2,What fundamental characteristics
metals have?
3,Please shade metallic elements in
periodic table and give some examples
of alloys.
4,Please list two principal advantages of
Al2O3 relative to metallic Al.
5,What’s the most limiting property of
ceramics.
The most limiting property of ceramics
brittleness
Recent development in ceramic technology are
expanding the utility of ceramics for structural
application not by eliminating their inherent
brittleness,but by increasing their strength to
sufficiently high levels (greater than 700MPa)
and increasing their resistance to fracture.
2,Al2O3 MgO SiO2 Si3N4
At least one metallic element +one of
five nonmetal element (C,N,O,P and S)
Carbide [5kB:baid]
Nitride [5naitraid]
Oxide [5Cksaid]
Phosphide [5fCsfaid]
Sulphide,[5sQlfaid]
Oxide
ceramics
Nonoxide
ceramics
3,One metallic element plus one of five
nonmetallic elements (C,N,O,P,or S)
4,Characteristics:
refractory
high hardness
high strength
high brittleness
? The similar structural feature of metals and
ceramics:
? Crystalline,their constituent atoms are
stacked together in a regular,repeating
pattern.
? The distinction,ceramics can be made in a
noncrystalline form,
[skI5mAt
Ik]
SiO2 (approximately 72%)
Na2O
CaO
Glass:
brittleness
similar with crystalline ceramic
transmit visible light
chemical inertness
glasses are important engineering
materials
Glass-ceramics is a third category
Lithium aluminosilicates
Certain glass compositions can be fully
devitified by an appropriate thermal
treatment
low-thermal expansion
coefficients
complex forms
high mechanical strength
Vitreous [5vItrIEs]
glassy state
Subsequent
crystallization
C Polymers(plastics)
Exempli gratia,For example.
1, ethylene
A colorless,flammable gas,C2H4,derived from
natural gas and petroleum and used as a source of
many organic compounds,in welding [5weldiN]焊接
and cutting metals,and as an anesthetic
[7Anis5Wetik]麻醉剂,2, polyethylene
A polymerized ethylene resin,used especially for
containers,kitchenware,and tubing,or in the form
of films and sheets for packaging.
3, e.g.
Any of numerous organic compounds,
such as benzene and methane,that
contain only carbon and hydrogen.
4, Acrylics [E5kriliks]丙烯酸树脂
5, Nylon [5nailEn]
Any of a family of high-strength,
resilient synthetic polymers,the molecules
of which contain the recurring amide
group CONH.
6, Hydrocarbon
These man-made materials
are a branch of organic chemistry,
? 1,Poly +mer,mer in a polymer
is a single hydrocarbon molecule
such as ethylene(C2H4),
? long chain olecules:
? Polymers are long-chain
molecules composed of many
mers bond together.
C H
2
C H
2
n
C H
2
C H
2
n
n
C H
2
C H
2
CC H
3
C H
3
C H
3
1) no brittleness
2,Characteristics,
2) lower melting point
3) high strength along it’s chain and low
strength between it’s chains
4) lightweight low-cost
5) higher chemical reactivity
6) Man-made materials
Substitution for
traditional structural metals
Qustions
1,please illustrate two type of elements that
composed ceramic compounds in periodic
table.
2,What are the major compositions of glass?
why glasses are important engineering
materials?
3,Please list two categories and give some
examples of ceramics according their
compositions.
4,Please list three categories and give some
examples of ceramics according their
atomic structrual feature.
5,What are polymers? What are
characteristics of polymers? Please give
some examples of polymers.
SiO2 (approximately 72%)
Na2O
CaO
Glass:
brittleness
similar with crystalline ceramic
transmit visible light
chemical inertness
glasses are important engineering
materials
? According to their compositions,
ceramics can be divided into two
catogories,One is oxide ceramics
such as aluminum oxide (Al2O3),
magnesium oxide (MgO),and silica
(SiO2),the other one is nonoxide
ceramics,silicon nitride is an
important nonoxide ceramic,
? according to their atomic structual
feature,there are three types of
ceramics as crystalline ceramics,
noncrystalline ceramics and the third
category,glass-ceramics,Silicon nitride
is one of crystalline ceramics,glass is a
kind of noncrystalline ceramics and
glass-ceramics is a relatively recent
material,that is,certain glass
compositions (such as lithium
aluminosilicates ) can be fully devitified
by an appropriate thermal treatment,
Polymers are long-chain molecules
composed of many mers bond
together,
Polyethylene,acrylics and nylon are all
typical polymers.
Polymers are no brittleness,high
strength along it’s chain and low
strength between it’s chains,
lightweight,low-cost,lower melting
point and higher chemical reactivity
compared with ceramics,at last
polymers are man-made materials.
shell
wood
D Composite (fiber reinforce plastics)
Possessing
hereditary[hI5redItErI] rank in
a political system or social class derived
from a feudalistic
[9fjU:dE`lIstIk] stage of a
country's development.
Inactive or inert.
1, Albeit [C:l5bi:It] page
12,line 5Even though; although; notwithstanding.
2, Noble page 12,para,2,line 2
? Combination of individual
materials from the previous
categories.
? Characteristics,the best of both
worlds
It carry along the superior
properties of each component,
producing a product that is
superior to either of the
components separately.
Example,fiberglass,wood,concrete,
s
Supplementary introduction
Semiconductors
A piece of equipment that produces a
powerful narrow beam of light that can be
used in medical operations,to cut metals,
or to make patterns of light for
entertainment,
1,arsenide [5B:sEnaid]砷化物
A compound of arsenic with a more
electropositive element.
2,laser
? Sophisticated
page 13,line 6 from below
[sE5fistikeitid] adj.
1.诡辩的,久经世故的
2.Very complex or complicated:
非常复杂精密或尖端的
? 最新最尖端的技术
the latest and most sophisticated
technology.
? Semiconductors are
relatively invisible compared
with polymers,but have a
comparable social impact.
? Semiconductors are the
basis of modern electronics.
A relatively small group of elements and
compounds has an important electrical
property。
? three semiconducting elements
(Si (silicon),Ge (germanium [dVE:5meiniEm] ),
Sn(tin)).
compounds,GaAs gallium[5^AliEm] arsenide,
CdS cadmium sulfide [5kAdmiEm
5sQlfaid]
? ceramics compound, ZnO
? Precise control of chemical purity
allows precise control of
electronic properties,
? Characteristics:
? semiconduction,in which they
are neither good electrical
conductors nor good electrical
insulators [5insjuleitE],instead,
their ability to conduct electricity
is intermediate [7intE5mi:djEt],
Atomic-scale-architecture
Composite
Devitrified[di:5vitrifai] 使不透明
Ductility
Electronic and magnetic material
Fiberglass
Materials selection
Microcircuitry [5maIkrEJs\:kIt][电
子 ]微电路
Microscopic-scale architecture
Refractory
Structural material
Qustions
1,Please define composites,and
then demonstrate the
characteristics of good
composites by some examples.
? 2,please enumerate
( [i5nju:mEreit] v.列举 )
semiconducting elements and
compounds.
Composite is material composed of a microscopic-
scale combination of individual materials from the
categories of metals,ceramics (and glasses),and
polymer.
E.g,fiberglass is a kind of composite system
composed of polymeric matrix reinforced with
glass fibers,Characteristic of fiberglass provides
the best of both worlds,It carry along the superior
properties of each component,producing a product
that is superior to either of the components
separately,The high strength of the small-diameter
glass fibers is combined with the ductility of the
polymer matrix to produce a strong material
capable of withstanding the normal loading
required of a structural material.
? There are three semiconducting elements (Si,Ge
and Sn) from column IVA and a cluster of
elements of the periodic table immediately
adjacent to column IVA,which forms
compounds that are semiconducting,Examples
include gallium arsenide (GaAs),which is used
as a high-temperature rectifier
([5rektifaiE] 整流器 ) and a laser
material,and cadmium sulfide (CdS) which is
used as a relatively low-cost solar cell for
conversion of solar energy to useful electrical
energy.
1.2 From structure to properties
The unit of luminous flux
[flQks]流量,通量 in the
International System,equal
to the amount of light given
out through a solid angle by
a source of one candela
[kAn5di:lE] intensity
radiating equally in all
directions,
1,hexagonal [hek`sA^EnEl]
Having six sides.
2,lumen[5lju:min]
缩写 lm [物理学 ] 流明
（光通量单位）：国际
度量系统中的光通量单
位，等于一烛光的均匀
点光源在单位主体角内
发出的光通量,
? Equivalent [i5kwivElEnt]
adj,相等的,相当的,同意义的
n,等价物,相等物
? Avenue [5Avinju:]
n,林荫道,大街,方法,途径,路
? Refraction [ri5frAkFEn]
n,折光,折射
Determination of the refractive
characteristics of the eye.
屈光度测定：对眼睛折射特性的测定
? Translucent [trAnz5lju:snt]
adj,半透明的,透明的
? Opaque [Eu5peik]
n,不透明物
adj.不透明的,不传热的,迟钝的
? Transparent [trAns5pZErEnt]
adj,透明的,显然的,明晰的
? Densification
[7densifi5keiFEn]
致密化
? To understand the properties
of engineering materials it is
necessary to understand their
structure,
Atomic-scale
architecture
10000000 times
Microscopic-scale
architecture
1000times
Example 1,Al,Mg
Al alloys are ductile
Mg alloys are brittle
Al structure follows a cubic
packing arrangement and Mg a
hexagonal one,
Example 2,transparent ceramics
Traditional ceramics contained a substantial
amount of residual porosity,
The porosity leads to loss of visible light
transmission,
Only about 0.3% porosity can cause Al2O3 to be
translucent,and 3% porosity can cause the
material to be completely opaque,
The elimination of porosity,
adding a small amount of impurity,
? The elimination of porosity resulted from
a relatively simple invention that
involved adding a small amount of
impurity (0.1 wt% MgO),which caused
the high-temperature densification
process for the Al2O3 powder to go to
completion.
? Poros microstructure in
polycrystalline Al2O3
? Figure 1
polycrystalline faceted
sapphires and rubies
Figure 3
polished discs with several dopants
(thickness,0.8 mm)
The two examples just cited
show typical and important
demonstrations of how properties
of engineering materials follow
directly from structure.
Qustions
? 1,Aluminum and magnesium are both metal,
why aluminum is relatively ductile while
magnesium is relatively brittle? Please explain
the dramatic effect that structure has on
properties on the atomic scale.
? 2,why traditional ceramics such as aluminum
oxide are opaque whereas recently optically
transparent aluminum oxide ceramics are
produced? What are the differences between their
microscopic-scale architectures?
1.3 Selection of materials
any of a group of very strong light weight,
synthetic fibers used in making radial tires,bullet
proof of vests,etc,
1, etc,
Latin the written abbreviation for et cetera,
used after a list to show that there are many other
similar things or people that you could have added,
and so forth,and so on,and the others
2, ASTM
American Society for Testing and Materials.
3, aramid
A polymer containing repeated amide groups,
as in various kinds of nylon.
4, Aromatic [7ArEu5mAtik]
Of,relating to,or containing one or more six-
carbon rings characteristic of the benzene
[5benzi:n,ben5zi:n] series and related
organic groups.
5, Polyamide
? Appreciation [E7pri:Fi5eiFEn]
n.
A judgment or opinion,especially a favorable
one。评价：判断或意见，尤指有益的。
? 2,Materials selection is the final,practical
decision in the engineering design process and
can determine that design’s ultimate success or
failure.
? 3,solid-state adj,使用电晶体的,不用真空管
的
? 4,indefinite [in5definit] adj.
不确定的,[语 ]不定的 (indefinite article)
? 5.although some structural ceramics can
withstand the anticipated service load,……
service load负载
? 6,criterion [krai5tiEriEn] n.
(批评判断的 )标准,准据,规范
critical [5kritikEl] adj.
评论的,鉴定的,批评的,危急的,临界的
? 7,The added cost of fabricating these more
sophisticated material systems is justified
only if a special advantage results.
fabricate [5fAbrikeit] vt.
制作,构成,捏造,伪造,虚构
Justify
To demonstrate or prove to be just,right,or
valid:
论证或证明 … 正当、正确或有效
? 8,optimal [5CptimEl] adj,最佳的,最
理想的
? 9,property comparison [kEm5pArisn]
? 10,junction [5dVQNkFEn] n.
连接,接合,交叉点,汇合处
? 10,
spherical [5sferikEl] adj.球的,球形的 ;
cylindrical [sI5lIndrIk(E)l] 圆柱的
? 11,integral [5inti^rEl] adj.
Essential or necessary for completeness; constituent:
必须的：构成整体所必须的；应有的
? 12,In the past quarter century,the term that
has come to label the general branch of
engineering concerned with materials is
materials science and engineering,This label
is accurate in that this field is a true blend of
fundamental,scientific studies and practical
engineering,It has grown to include
contributions from many traditional fields,
including metallurgy,ceramic engineering,
polymer chemistry,solid-state physics,and
physical chemistry.
? Label [5leibl] vt
To identify or designate with a label; describe
or classify:
把 … 归类，描述：用标签分别或命名；描绘
或归类
? contribution
[7kCntri5bju:FEn] n.捐献,
贡献,投稿
? metallurgy [me5tAlEdVi] n,冶金,冶
金术
? 13,optimum [5CptimEm]
n.最适宜
adj.最适宜的
Which material do I now
select for a particular
application?
? Two separate decisions:
? First:
? One must decide which type of
material is appropriate.
? Second:
? The best specific material within
that category must be found.
? preferable [5prefErEbl]
? adj.更可取的,更好的,更优越的
A, Competition among the
five types of materials
B, Selecting an optimal metal
property comparisons must be made
2, Cost
1, Superior mechanical properties
c,Selecting a metal
substitute
1.4 materials science and
engineering
? First, science
? Second, materials
? Finally,
engineering
Materials Science and
Engineering
Guan Rui-fang
材料与新技术革命
材料与国防现代化
? This book is divided into four
major sections
I,The fundamentals
II,The structural materials
III,The electronic and magnetic
materials
IV,Materials in engineering design
science
materials
engineering
? Nature of materials’
properties
? Microscopic or
submicroscopic
structure
? Engineering
design
Chapter I
Materials for Engineering
1.1 Types of materials
1.2 From structure to properties
1.3 Selection of materials
1.4 Materials science and
engineering
Key word
? Alloy [5AlCi]
? Atomic-scale-architecture
? Brittle [5britl]
? Ceramic [si5rAmik]
? Composite [5kCmpEzit,-
zait]
? Concrete [5kCnkri:t]
? Conductor
? Crystalline [5kristElain] adj.
? Devitrified [di:5vitrifai]
? Ductility [dQk5tiliti]
? Electronic and magnetic material
? Element [5elimEnt]
? Fiberglass [5faIbE^lB:s]
? Glass
? Glass-ceramic
? Insulator
? Materials science and engineering
? Materials selection
? Metallic
? Microcircuitry
[5maIkrEJs\:kIt]
? Microscopic-scale architecture
? Noncrystalline
? Nonmetallic [5nCnmi5tAlik]
Key word
? Oxide
? Periodic[piEri5Cdik]
table
? Plastic
? Polyethylene
[7pCli5eWili:n]
? Polymer
? Property
? Refractory
? Semiconductor
? Silica硅石,SiO2
? Silicate]硅酸盐
? Silicon硅元素
? Steel
? Structural material
? wood
Key word
1.1 Types of materials
? a, Metals metallic bond
? b, Ceramics (glass) ionic [aI5RnIk]
and covalent [kEu5veilEnt] bond
? c, Polymers covalent and Van der waals
bond
? d, Composites
? e, semiconductors
What materials are available to me?
Five categories
A Metals
超塑性的,超塑性材料 (制 )的
1, i.e.
Latin,the written abbreviation for id est,
也就是，即。 读作,that is
2, state-of-the-art
技术发展水平，现代化的。
3, superplastic.
? Characteristics(metallic 金属的，金属性的 )
? It is strong and can be readily formed into
practical shapes,
? Ductile [5dQktail] — permanent
deformability
? metallic luster
? electric conductor
Metals have no brittleness and are safe for
many applications.
Structural steel
Gasket
[5^Ask
it]
垫圈,衬垫
spring wire
Valve [vAlv]
B Ceramics [si5rAmiks]
A homogeneous mixture of two or more substances,
which may be solids,liquids,gases,or a combination of
these,
1, Refractory [ri5frAktEri]
Difficult to melt or work; resistant to heat.
2, fracture toughness 断裂韧度
3, crystalline[5kristElain]
Being,relating to,or composed of crystal or crystals.
4, Devitrify [di:5vitrifai]
To cause (a glassy material) to become crystalline and
brittle.
5, solution
? The ceramics is derived from
Greek word,keramic” which
means an art of potter,
Include,
? glass ; enamels [i5nAmEl] ;
refractories ; cements ;
? limes ; plasters(plaster of Paris) ;
cermets[5sE:met]金属陶瓷,含陶合金 ;
? electronic ceramics ;
? high and low tension electrical
insulators ;
? structural clay products ; nuclear
ceramics ;
? whitewares ; abrasives [E5breisiv],
The Different Colors of
Corundum [kE5rQndEm]
Ruby
Sapphire
[5sAfaiE]
Why shouldn’t Al2O3 be chosen for
certain applications where metallic
aluminum has been used?
1,Al2O3 have two advantages:
first,chemically stable ;
Al oxidized
second,higher melting point (20200C)
Al (6600C)
refractory
use in industrial furnace
construction
Questions
1,What materials are available to you in
this book?
2,What fundamental characteristics
metals have?
3,Please shade metallic elements in
periodic table and give some examples
of alloys.
4,Please list two principal advantages of
Al2O3 relative to metallic Al.
5,What’s the most limiting property of
ceramics.
The most limiting property of ceramics
brittleness
Recent development in ceramic technology are
expanding the utility of ceramics for structural
application not by eliminating their inherent
brittleness,but by increasing their strength to
sufficiently high levels (greater than 700MPa)
and increasing their resistance to fracture.
2,Al2O3 MgO SiO2 Si3N4
At least one metallic element +one of
five nonmetal element (C,N,O,P and S)
Carbide [5kB:baid]
Nitride [5naitraid]
Oxide [5Cksaid]
Phosphide [5fCsfaid]
Sulphide,[5sQlfaid]
Oxide
ceramics
Nonoxide
ceramics
3,One metallic element plus one of five
nonmetallic elements (C,N,O,P,or S)
4,Characteristics:
refractory
high hardness
high strength
high brittleness
? The similar structural feature of metals and
ceramics:
? Crystalline,their constituent atoms are
stacked together in a regular,repeating
pattern.
? The distinction,ceramics can be made in a
noncrystalline form,
[skI5mAt
Ik]
SiO2 (approximately 72%)
Na2O
CaO
Glass:
brittleness
similar with crystalline ceramic
transmit visible light
chemical inertness
glasses are important engineering
materials
Glass-ceramics is a third category
Lithium aluminosilicates
Certain glass compositions can be fully
devitified by an appropriate thermal
treatment
low-thermal expansion
coefficients
complex forms
high mechanical strength
Vitreous [5vItrIEs]
glassy state
Subsequent
crystallization
C Polymers(plastics)
Exempli gratia,For example.
1, ethylene
A colorless,flammable gas,C2H4,derived from
natural gas and petroleum and used as a source of
many organic compounds,in welding [5weldiN]焊接
and cutting metals,and as an anesthetic
[7Anis5Wetik]麻醉剂,2, polyethylene
A polymerized ethylene resin,used especially for
containers,kitchenware,and tubing,or in the form
of films and sheets for packaging.
3, e.g.
Any of numerous organic compounds,
such as benzene and methane,that
contain only carbon and hydrogen.
4, Acrylics [E5kriliks]丙烯酸树脂
5, Nylon [5nailEn]
Any of a family of high-strength,
resilient synthetic polymers,the molecules
of which contain the recurring amide
group CONH.
6, Hydrocarbon
These man-made materials
are a branch of organic chemistry,
? 1,Poly +mer,mer in a polymer
is a single hydrocarbon molecule
such as ethylene(C2H4),
? long chain olecules:
? Polymers are long-chain
molecules composed of many
mers bond together.
C H
2
C H
2
n
C H
2
C H
2
n
n
C H
2
C H
2
CC H
3
C H
3
C H
3
1) no brittleness
2,Characteristics,
2) lower melting point
3) high strength along it’s chain and low
strength between it’s chains
4) lightweight low-cost
5) higher chemical reactivity
6) Man-made materials
Substitution for
traditional structural metals
Qustions
1,please illustrate two type of elements that
composed ceramic compounds in periodic
table.
2,What are the major compositions of glass?
why glasses are important engineering
materials?
3,Please list two categories and give some
examples of ceramics according their
compositions.
4,Please list three categories and give some
examples of ceramics according their
atomic structrual feature.
5,What are polymers? What are
characteristics of polymers? Please give
some examples of polymers.
SiO2 (approximately 72%)
Na2O
CaO
Glass:
brittleness
similar with crystalline ceramic
transmit visible light
chemical inertness
glasses are important engineering
materials
? According to their compositions,
ceramics can be divided into two
catogories,One is oxide ceramics
such as aluminum oxide (Al2O3),
magnesium oxide (MgO),and silica
(SiO2),the other one is nonoxide
ceramics,silicon nitride is an
important nonoxide ceramic,
? according to their atomic structual
feature,there are three types of
ceramics as crystalline ceramics,
noncrystalline ceramics and the third
category,glass-ceramics,Silicon nitride
is one of crystalline ceramics,glass is a
kind of noncrystalline ceramics and
glass-ceramics is a relatively recent
material,that is,certain glass
compositions (such as lithium
aluminosilicates ) can be fully devitified
by an appropriate thermal treatment,
Polymers are long-chain molecules
composed of many mers bond
together,
Polyethylene,acrylics and nylon are all
typical polymers.
Polymers are no brittleness,high
strength along it’s chain and low
strength between it’s chains,
lightweight,low-cost,lower melting
point and higher chemical reactivity
compared with ceramics,at last
polymers are man-made materials.
shell
wood
D Composite (fiber reinforce plastics)
Possessing
hereditary[hI5redItErI] rank in
a political system or social class derived
from a feudalistic
[9fjU:dE`lIstIk] stage of a
country's development.
Inactive or inert.
1, Albeit [C:l5bi:It] page
12,line 5Even though; although; notwithstanding.
2, Noble page 12,para,2,line 2
? Combination of individual
materials from the previous
categories.
? Characteristics,the best of both
worlds
It carry along the superior
properties of each component,
producing a product that is
superior to either of the
components separately.
Example,fiberglass,wood,concrete,
s
Supplementary introduction
Semiconductors
A piece of equipment that produces a
powerful narrow beam of light that can be
used in medical operations,to cut metals,
or to make patterns of light for
entertainment,
1,arsenide [5B:sEnaid]砷化物
A compound of arsenic with a more
electropositive element.
2,laser
? Sophisticated
page 13,line 6 from below
[sE5fistikeitid] adj.
1.诡辩的,久经世故的
2.Very complex or complicated:
非常复杂精密或尖端的
? 最新最尖端的技术
the latest and most sophisticated
technology.
? Semiconductors are
relatively invisible compared
with polymers,but have a
comparable social impact.
? Semiconductors are the
basis of modern electronics.
A relatively small group of elements and
compounds has an important electrical
property。
? three semiconducting elements
(Si (silicon),Ge (germanium [dVE:5meiniEm] ),
Sn(tin)).
compounds,GaAs gallium[5^AliEm] arsenide,
CdS cadmium sulfide [5kAdmiEm
5sQlfaid]
? ceramics compound, ZnO
? Precise control of chemical purity
allows precise control of
electronic properties,
? Characteristics:
? semiconduction,in which they
are neither good electrical
conductors nor good electrical
insulators [5insjuleitE],instead,
their ability to conduct electricity
is intermediate [7intE5mi:djEt],
Atomic-scale-architecture
Composite
Devitrified[di:5vitrifai] 使不透明
Ductility
Electronic and magnetic material
Fiberglass
Materials selection
Microcircuitry [5maIkrEJs\:kIt][电
子 ]微电路
Microscopic-scale architecture
Refractory
Structural material
Qustions
1,Please define composites,and
then demonstrate the
characteristics of good
composites by some examples.
? 2,please enumerate
( [i5nju:mEreit] v.列举 )
semiconducting elements and
compounds.
Composite is material composed of a microscopic-
scale combination of individual materials from the
categories of metals,ceramics (and glasses),and
polymer.
E.g,fiberglass is a kind of composite system
composed of polymeric matrix reinforced with
glass fibers,Characteristic of fiberglass provides
the best of both worlds,It carry along the superior
properties of each component,producing a product
that is superior to either of the components
separately,The high strength of the small-diameter
glass fibers is combined with the ductility of the
polymer matrix to produce a strong material
capable of withstanding the normal loading
required of a structural material.
? There are three semiconducting elements (Si,Ge
and Sn) from column IVA and a cluster of
elements of the periodic table immediately
adjacent to column IVA,which forms
compounds that are semiconducting,Examples
include gallium arsenide (GaAs),which is used
as a high-temperature rectifier
([5rektifaiE] 整流器 ) and a laser
material,and cadmium sulfide (CdS) which is
used as a relatively low-cost solar cell for
conversion of solar energy to useful electrical
energy.
1.2 From structure to properties
The unit of luminous flux
[flQks]流量,通量 in the
International System,equal
to the amount of light given
out through a solid angle by
a source of one candela
[kAn5di:lE] intensity
radiating equally in all
directions,
1,hexagonal [hek`sA^EnEl]
Having six sides.
2,lumen[5lju:min]
缩写 lm [物理学 ] 流明
（光通量单位）：国际
度量系统中的光通量单
位，等于一烛光的均匀
点光源在单位主体角内
发出的光通量,
? Equivalent [i5kwivElEnt]
adj,相等的,相当的,同意义的
n,等价物,相等物
? Avenue [5Avinju:]
n,林荫道,大街,方法,途径,路
? Refraction [ri5frAkFEn]
n,折光,折射
Determination of the refractive
characteristics of the eye.
屈光度测定：对眼睛折射特性的测定
? Translucent [trAnz5lju:snt]
adj,半透明的,透明的
? Opaque [Eu5peik]
n,不透明物
adj.不透明的,不传热的,迟钝的
? Transparent [trAns5pZErEnt]
adj,透明的,显然的,明晰的
? Densification
[7densifi5keiFEn]
致密化
? To understand the properties
of engineering materials it is
necessary to understand their
structure,
Atomic-scale
architecture
10000000 times
Microscopic-scale
architecture
1000times
Example 1,Al,Mg
Al alloys are ductile
Mg alloys are brittle
Al structure follows a cubic
packing arrangement and Mg a
hexagonal one,
Example 2,transparent ceramics
Traditional ceramics contained a substantial
amount of residual porosity,
The porosity leads to loss of visible light
transmission,
Only about 0.3% porosity can cause Al2O3 to be
translucent,and 3% porosity can cause the
material to be completely opaque,
The elimination of porosity,
adding a small amount of impurity,
? The elimination of porosity resulted from
a relatively simple invention that
involved adding a small amount of
impurity (0.1 wt% MgO),which caused
the high-temperature densification
process for the Al2O3 powder to go to
completion.
? Poros microstructure in
polycrystalline Al2O3
? Figure 1
polycrystalline faceted
sapphires and rubies
Figure 3
polished discs with several dopants
(thickness,0.8 mm)
The two examples just cited
show typical and important
demonstrations of how properties
of engineering materials follow
directly from structure.
Qustions
? 1,Aluminum and magnesium are both metal,
why aluminum is relatively ductile while
magnesium is relatively brittle? Please explain
the dramatic effect that structure has on
properties on the atomic scale.
? 2,why traditional ceramics such as aluminum
oxide are opaque whereas recently optically
transparent aluminum oxide ceramics are
produced? What are the differences between their
microscopic-scale architectures?
1.3 Selection of materials
any of a group of very strong light weight,
synthetic fibers used in making radial tires,bullet
proof of vests,etc,
1, etc,
Latin the written abbreviation for et cetera,
used after a list to show that there are many other
similar things or people that you could have added,
and so forth,and so on,and the others
2, ASTM
American Society for Testing and Materials.
3, aramid
A polymer containing repeated amide groups,
as in various kinds of nylon.
4, Aromatic [7ArEu5mAtik]
Of,relating to,or containing one or more six-
carbon rings characteristic of the benzene
[5benzi:n,ben5zi:n] series and related
organic groups.
5, Polyamide
? Appreciation [E7pri:Fi5eiFEn]
n.
A judgment or opinion,especially a favorable
one。评价：判断或意见，尤指有益的。
? 2,Materials selection is the final,practical
decision in the engineering design process and
can determine that design’s ultimate success or
failure.
? 3,solid-state adj,使用电晶体的,不用真空管
的
? 4,indefinite [in5definit] adj.
不确定的,[语 ]不定的 (indefinite article)
? 5.although some structural ceramics can
withstand the anticipated service load,……
service load负载
? 6,criterion [krai5tiEriEn] n.
(批评判断的 )标准,准据,规范
critical [5kritikEl] adj.
评论的,鉴定的,批评的,危急的,临界的
? 7,The added cost of fabricating these more
sophisticated material systems is justified
only if a special advantage results.
fabricate [5fAbrikeit] vt.
制作,构成,捏造,伪造,虚构
Justify
To demonstrate or prove to be just,right,or
valid:
论证或证明 … 正当、正确或有效
? 8,optimal [5CptimEl] adj,最佳的,最
理想的
? 9,property comparison [kEm5pArisn]
? 10,junction [5dVQNkFEn] n.
连接,接合,交叉点,汇合处
? 10,
spherical [5sferikEl] adj.球的,球形的 ;
cylindrical [sI5lIndrIk(E)l] 圆柱的
? 11,integral [5inti^rEl] adj.
Essential or necessary for completeness; constituent:
必须的：构成整体所必须的；应有的
? 12,In the past quarter century,the term that
has come to label the general branch of
engineering concerned with materials is
materials science and engineering,This label
is accurate in that this field is a true blend of
fundamental,scientific studies and practical
engineering,It has grown to include
contributions from many traditional fields,
including metallurgy,ceramic engineering,
polymer chemistry,solid-state physics,and
physical chemistry.
? Label [5leibl] vt
To identify or designate with a label; describe
or classify:
把 … 归类，描述：用标签分别或命名；描绘
或归类
? contribution
[7kCntri5bju:FEn] n.捐献,
贡献,投稿
? metallurgy [me5tAlEdVi] n,冶金,冶
金术
? 13,optimum [5CptimEm]
n.最适宜
adj.最适宜的
Which material do I now
select for a particular
application?
? Two separate decisions:
? First:
? One must decide which type of
material is appropriate.
? Second:
? The best specific material within
that category must be found.
? preferable [5prefErEbl]
? adj.更可取的,更好的,更优越的
A, Competition among the
five types of materials
B, Selecting an optimal metal
property comparisons must be made
2, Cost
1, Superior mechanical properties
c,Selecting a metal
substitute
1.4 materials science and
engineering
? First, science
? Second, materials
? Finally,
engineering
