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一、名词解释
Reaction
bonding
：
A ceramic
processing technique by which a shape is made
using one material
that is later
converted into a ceramic material by reaction with
a gas.
Materials
science
and
engineering
:
is
an
interdisciplinary
field
concerned
with
inventing
new
materials and improving previously
known materials by developing a deeper
understanding of the
microstructure-composition-synthesis-
processing
relationships.
Structure : means a description of the
arrangements of
atoms or
ions in a material
Composition: means
the chemical make-up of a
material.
Trans-granular
(
晶内的，穿晶的
) Fracture -
fracture in which cracks would go through the
grains.
Ductile Fracture In metals that
have good ductility and toughness, ductile
fracture normally occurs
in
a
trans-granular
,
a
considerable
amount
of
deformation-including
necking
is
observed in
the
failed component
shot peening
A process in which metal
spheres are shot at a leads to a residual
compressive stress at the surface of a
component and this enhances fatigue life.
Flexural
modulus : The modulus of elasticity calculated
from the results of a bend test, giving the
slope of the stress-
deflection(
偏转
) curve
Tempering
A
low
–
temperature heat treatment
used to reduce the hardness of martensite
(
马氏
体
)by
permitting the martensite
to begin to decompose to the
equilibrium phase.
Stress : Force or
load per unit area of cross-section
(
横界面
) over which the force
or load is acting
Strain : Elongation
(
延长
) change in dimension
per unit length.
Young’s modulus
: The slope
(
斜率
) of the linear
(
线性的
) part of the
stress-strain curve in the
elastic (
弹性
的
) region
(
区域的
), same as modulus of
elasticity (
弹性
系数
).
Synthesis
:
is
the
process
by
which
materials
are
made
from
naturally
occurring
or
other
chemicals
Processing : means
different ways for shaping materials into useful
components or changing their
properties.
Weibull
distribution
:
A
mathematical
distribution
showing
the
probability
of
failure
or
survival of a material
as a
function of
the stress.
Aspect ratio
(
纵横比
) - The
length of a fiber divided by its diameter.
Delamination : Separation of individual
plies of
a fiber-reinforced
composite.
Ductile to brittle
transition temperature (DBTT) :The temperature
below which a material behaves
in a
brittle manner in an impact test
Creep
rate
The rate at which a
material deforms when a stress is applied at a
high temperature
Rupture
time
The
time
required
for
a
specimen
to
fail
by
creep
at
a
particular
temperature
and
stress
Fatigue
life
The
number
of
cycles
permitted
at
a
particular
stress
before
a
material
fails
by
fatigue
Endurance limit An older concept that
defined a stress below which a material will not
fail in a
fatigue test.
Tape
casting
：
A process for
making thin sheets of ceramics
using a ceramic slurry consisting of
binders (
粘结剂
),
plasticizers(
可塑剂
), etc. The
slurry is cast with the help of a
blade(
刀片
) onto
a
plastic
substrate.
Fatigue
strength : The stress required to cause failure by
fatigue in a given number of cycles, such
as 500 million
cycles.
Notch sensitivity
: Measures the effect of a
notch, scratch (
剐擦敏感度
)-, or
other imperfection
（不完整性
,
非理想性）
on a
material’s properties, such as toughness or
fatigue life
Linear polymer
Any polymer in which
molecules are in the form of spaghetti-like chains
(
类似
与意大利细面条
).
Brittle stress-rupture failures :
usually show little necking and occur more often
at smaller creep
rates and high
temperatures.
Rule of
mixtures
The
statement that the properties of a
composite
material are a function of
the volume fraction of each
material in the composite
Cemented
carbides
(
烧结碳化物
)-
Particulate
composites
containing
hard
ceramic
particles
bonded with a soft metallic matrix.
Electrical
Contacts
(
电接触材料
)
–
Materials,
used
for
electrical
contacts
in
switches
and
rela
ys(
继
电
器
)
must
have
a
good
combination
of
wear
resistance
and
electrical
conductivity.
Polymers
these
materials
are
made
up
of
many
(poly)
identical
chemical
units
(mers)
that
are
joined together to
construct giant molecules
(
巨大的分子
).
Tensile toughness : the energy absorbed
by a material prior to
fracturing(
断裂
)
Ductility : the amount of deformation
that a material can withstand without breaking
Creep : a time dependent, permanent
deformation at high temperature, occurring at
constant load
or constant stress
True strain : The strain calculated
using actual and not
original dimensions, given by
?
t = ln(l/l0)
=ln(A/A0)
True
stress : The load divided
by the actual cross-sectional area of the specimen
at that load.
Glass-ceramics
are
crystalline
materials
that
are
derived
from
amorphous
glasses.
Usually,
glass-ceramics have
a substantial level of crystallinity (~>70-99%).
Copolymer
An
addition polymer produced by more than one type of
monomer.
Addition Polymerization
Process by which polymer
chains are built up by adding monomers
(
单
体
) together
without creating a
byproduct(
副产品
).
Condensation Polymerization A
polymerization mechanism in which a small molecule
(e.g., water,
methanol, etc.) is
condensed out as a byproduct
Deflection
temperature The tamperture at which a polymer will
deform a given amount under a
standard
load.
Degree
of
Polymerization
The
average
molecular
weight
of
the
polymer
divided
by
the
molecular weight of the monomer.
Injection molding
：
A processing technique
inwhich a
thermoplastic
mass (loaded with ceramic
powder) is
mixed in an extruder-like setup and then injected
into a die to form complex parts. In
the case of ceramics, the thermoplastic
is burnt off.
Conchoidal fracture
:(
贝壳状的断裂
) Fracture surface
containing a very
smooth mirror zone
near the origin of the fracture, with
tear lines comprising the remainder of the
surface.
Poisson’s
ratio
: longitudinal elastic
deformation (
纵向变形
) to the
lateral deformation
（横向变
形）
occurring at the same time by a tensile
or compressive stress.
Powder
metallurgy
：
Powder
processing routes used for converting metal and
alloy powders into
useful shapes