材料英语证书考试(PEC)-材料试验词汇.doc

材料英语证书考试(PEC)-材料试验词汇

A
Adherence—The extent to which a coating bonds to a substrate.

Adherence Index--Measure of the Adherence of porcelain enamel and ceramic coatings to
sheet metal.

Alpha Rockwell Hardness—Index of the resistance of a plastic to surface penetration by a
specified indenter under specified load applied with a Rockwell Hardness tester. Higher values
indicate higher indentation Hardness.

Axial Strain—The Strain in the direction that the load is applied, or on the same axis as the
applied load.

Analogue board—A machine circuit board, which converts analogue signals into digital signal.

Anchor Pin—A steel pin that connects a grip or jig to an eye end

Auto Return—Auto Return, when set to on, causes the crosshead to return automatically to its
Zero point at the end of the test.

B
Bend Test—Method for measuring Ductility of certain materials. There are no standardized
terms for reporting bend test results for broad classes of materials; rather, terms associated with
bend tests apply to specific forms or types of materials. For example, materials specifications
sometimes require that a specimen be bent to a specified inside diameter (ASTM A-360, steel
products). A bend test for Ductility of welds is given in ASTM E-190. Results of tests of
fiberboard are reported by a description of the failure or photographs.

Bending Strength—Alternate term for Flexural Strength. It is most commonly used to describe
flexure properties of cast iron and wood products.

Bond Strength—Stress (tensile load divided by area of bond) required to rupture a bond formed
by an adhesive between two metal blocks.

Break Elongation—The Elongation of the specimen to the break point.

Breaking Load—Load which causes fracture in a tensile, compression, flexure or Torsion Test.
In tensile tests of textiles and yarns, breaking load also is called breaking strength. In tensile
tests of thin sheet materials or materials in form of small diameter wire it is difficult to
distinguish between breaking load and the maximum load developed, so the latter is considered
the breaking load.

Breaking Strength—Stress required rupturing the specimen.

GLOSSARY OF MATERIALS TESTING

Bulk Modulus of Elasticity—Ratio of Stress to change in volume of a material subjected to
axial loading. Related to Modulus of Elasticity (E) and Poisson's Ratio (r) by the following
equation: Bulk Modulus K=E/3(1-2r).

Cleavage Strength—Tensile load required to cause separation of a 1-in. long metal-to-metal
adhesive bond under the conditions set in ASTM D-1062.

Climbing Drum Peel Test—Method for determining Peel Resistance of adhesive bond between
a relatively flexible and a rigid material. (ASTM D-1781).

Coefficient of Elasticity—An alternate term for Modulus of Elasticity.

Cohesive Strength—Theoretical Stress that causes fracture in tensile test if material exhibits no

plastic deformation.

Complex Modulus—Measure of dynamic mechanical properties of a material, taking into
account energy dissipated as heat during deformation and Recovery. It is equal to the sum of
static modulus of a material and its loss modulus. In the case of shear loading, it is called
dynamic modulus.

Compressibility—Extent to which a material is compressed in test for compressibility and
Recovery of gasket materials. It is usually reported with Recovery.

Compressibility and Recovery Test—Method for measuring behavior of gasket materials under
short time compressive loading at room temperature. ASTM F-36 outlines a standard procedure.
This test is not designed to indicate long term (creep) behavior and should not be confused
with the plastometer test.

Compression—Typically a direction of force applied to a sample to decrease its height

Compression Fatigue—Ability of rubber to sustain repeated fluctuating compressive loads.
(ASTM D-623)

Compression set—The extent to which rubber is permanently deformed by a prolonged
compressive load (ASTM D-395). Should not be confused with low temperature compression
set.

Compression test—Method for determining behavior of materials under crushing loads.
Specimen is compressed, and deformation at various loads is recorded. Compressive stress and
strain are calculated and plotted as a stress-strain diagram which is used to determine elastic
limit, proportional limit, yield point, Yield Strength and (for some materials) compressive
strength. Standard compression tests are given in ASTM C-773 (high strength ceramics),
ASTM E-9 (metals), ASTM E-209 (metals at elevated temperatures) and ASTM D-695

(plastics).

Compression-Deflection Test—Nondestructive method for determining relationship between
compressive load and deflection under load for specimen

Compressive Deformation—Extent to which a material deforms under a Crushing Load.

Compressive Strength—Maximum stress a material can sustain under crush loading.
Compressive strength is calculated by dividing the maximum load by the original
cross-sectional area of a specimen in a compression test.

Compressive Yield Strength—Stress which causes a material to exhibit a specified deformation.
Usually it is determined from the stress-strain diagram obtained in a compression test.

Creep—Deformation that occurs over a period of time when a material is subjected to constant
stress at constant temperature. In metals, creep usually occurs only at elevated temperatures.
Creep at room temperature is more common in plastic materials and is called cold flow or
deformation under load. Data obtained in a creep test usually is presented as a plot of creep vs.
time with stress and temperature constant. Slope of the curve is creep rate and end point of the
curve is Time for Rupture. As indicated in the accompanying diagram, the creep of a material
can be divided into three stages First stage, or primary creep, starts at a rapid rate and slows
with time. Second stage (secondary) creep has a relatively uniform rate. Third stage (tertiary)
creep has an accelerating creep rate and terminates by failure of material at Time for Rupture.

Creep Limit—Alternate term for Creep Strength.

Creep Rate—Time rate of deformation of a material subject to Stress at a constant temperature.
It is the slope of the creep vs. time diagram obtained in a creep test. Units usually are in/in/hr
or % of elongation/hr. Minimum creep rate is the slope of the portion of the creep vs. time
diagram corresponding to secondary creep.

Creep Recovery—Rate of decrease in deformation that occurs when load is removed after

prolonged application in a Creep Test. Constant temperature is maintained to eliminate effects
of thermal expansion, and measurements are taken from time load is zero to eliminate elastic
effects.

Creep Rupture Strength—Stress required to cause fracture in a creep test within a specified
time. Alternate term is Stress Rupture Strength.

Creep Strength—Maximum Stress required to cause a specified amount of creep in a specified
time Also used to describe maximum Stress that can be generated in a material at constant
temperature under which creep rate decreases with time. An alternate term is creep limit.

Creep Test—Method for determining creep or stress relaxation behavior. To determine creep
properties, material is subjected to prolonged constant tension or compression loading at
constant temperature. Deformation is recorded at specified time intervals and a creep vs. time
diagram is plotted. Slope of curve at any point is creep rate. If failure occurs, it terminates test
and Time for Rupture is recorded. If specimen does not fracture within test period, creep
recovery may be measured. To determine stress relaxation of material, specimen is deformed a
given amount and decrease in stress over prolonged period of exposure at constant temperature
is recorded. Standard creep testing procedures are detailed in ASTM E-139, ASTM D-2990 and
D-2991 (plastics) and ASTM D-2294 (adhesives).

Crush Resistance—Load required to produce fracture in a glass sphere subjected to crush
loading. (ASTM D-1213).

Crushing Load—Maximum compressive force applied during a compression or crushing test.

For materials that do not shatter, crushing load is defined as the force required to produce a
specified type of failure.

Crushing Strength—Compressive load required to cause a crack to form in a sintered metal
powder bearing (ASTM B-438 and B-439). Cold crushing strength of refractory bricks and
shapes is the gross compressive Stress required to cause fracture. (ASTM C-133).

Compounding—The combination of polymers with other materials either by means of
mechanical (dry) blending or melt state blending

Crosshead—This is the main beam on the testing machine. It is this beam that moves either up
or down producing a compressive or tensile force. A grip is attached to the crosshead and the
test piece is attached to the grip. The distance that the crosshead moves through is measured
from a rotating optical sensor.

Crosshead Loom—A ribbon cable that connects the moving crosshead to the machine
electronics, to supply the load cell with a voltage and supply the machine with a load signal.

D

Deformation Energy—Energy required to deform a material a specified amount. It is the area
under the Stress-Strain Diagram up to a specified strain.

Deformation Under Load—Measure of the ability of rigid plastics to withstand permanent
deformation and the ability of nonrigid plastics to return to original shape after deformation.
Standard test methods for determining both types of deformation under load are given in
ASTM D-621. For rigid plastics, deformation is re-ported as % change in height of specimen
after 24 hours under a specified load. For nonrigid plastics, results are reported as % change in
height after 3 hours under load and Recovery in the 1-1/2 hour period following removal of the
load. Recovery is % increase in height calculated on basis of original height.

Delamination Strength—Measure of the node-to-node Bond Strength of honeycomb core
materials. It is equal to the tensile load applied to a honeycomb panel at fracture divided by its
width times its thickness. (ASTM C-363)

Denier—The unit of linear density equal to the mass in grams per 9000 m of fiber, yarn, or
other textile strand.

Dry Strength—Strength of an adhesive joint determined immediately after drying or after a
period of conditioning in a specified atmosphere. (ASTM D-2475)

Ductility—Extent to which a material can sustain plastic deformation without rupture.
Elongation and Reduction of Area are common indices of ductility.

Dynamic Creep—Creep that occurs under fluctuating load or temperature.

Die swell—Whenever a polymer melt emerges from a die the diameter or thickness is always
larger than the diameter (or gap) of the die.At usual production throughputs,diameter or
thickness ratios range from 1.20-1.40 for PVC to 1.50-2.00 for commercial grade
Polyethyene’s and much more for some polymers containing a high molecular weight tail.It is
an indication of the elasticity of the polymer.The more elastic polymers give larger swell.Of
course,by pulling the extrudates the swell is reduced and of course extrudates can be drawn
down to diameters(or thickness) much smaller than the die diameter or gap.

Diameter—Used where the cross section shape of the test piece is round.

E
EASL（Elongation at a specified load）

Eccentricity of Loading—Distance between the actual line of action of compressive or tensile
loads and the line of action that would produce a uniform Stress over the cross section of the
specimen.

Edge Tearing Strength—Measure of the resistance of paper to tearing when folded over a

V-notch beam and loaded in a tensile testing machine. Results are re-ported in lb or kg. (See
Tear Resistance)

Elastic Hysteresis—Difference between strain energy required to generate a given Stress in a
material and elastic energy at that Stress. It is the energy dissipated as heat in a material in one
cycle of dynamic testing. Elastic hysteresis divided by elastic deformation energy is equal to
damping capacity.

Elastic Limit—Greatest Stress that can be applied to a material without causing permanent
deformation. For metals and other materials that have a significant straight line portion in their
Stress/strain diagram, elastic limit is approximately equal to proportional limit. For materials
that do not exhibit a significant proportional limit, elastic limit is an arbitrary approximation
(the apparent elastic limit).

Elastic Limit, Apparent—Arbitrary approximation of the elastic limit of materials that do not
have a significant straight line portion on a Stress/strain diagram. It is equal to the Stress at
which the rate of strain is 50% greater than at zero Stress. It is the Stress at the point of
tangency between the Stress-Elastic Hysteresis strain curve and the line having a slope, with
respect to the Stress axis, 50% greater than the slope of the curve at the origin.

Elasticity—Ability of a material to return to its original shape when load causing deformation
is removed.

Elongation—Measure of the ductility of a material determined in a Tensile Test. It is the
increase in gage length (measured after rupture) divided by original gage length. Higher
elongation indicates higher ductility. Elongation cannot be used to predict behavior of materials
subjected to sudden or repeated loading.

Embrittlement—Reduction in ductility due to physical or chemical changes.
Endurance—Alternate term for Fatigue Limit.

Engineering Stress—Load applied to a specimen in a tension or compression test divided by
the cross-sectional area of the specimen. The change in cross-sectional area that occurs with
increases and decreases in applied load, is disregarded in computing engineering Stress. It is
also called conventional Stress.

Extensometer—Instrument for measuring changes in linear dimensions. Also called a Strain
gauge. Frequently based on Strain gauge technology.

Eye End—An adapter that fits to a load cell or machine, that enables grip or jigs to be attached

F
Fatigue—Permanent structural change that occurs in a material subjected to fluctuating Stress
and strain. However, in the case of glass, fatigue is determined by long-term static testing and

is analogous to Stress rupture in other materials. In general, fatigue failure can occur with
Stress levels below the elastic limit.

Fatigue Life—Number of cycles of fluctuating Stress and strain of a specified nature that a
material will sustain before failure occurs. Fatigue lif