ASTM C1359-96(2000)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:C1359–96 (Reapproved 2000)
Standard Test Method for
Monotonic Tensile Strength Testing of Continuous Fiber-
Reinforced Advanced Ceramics With Solid Rectangular
Cross-Section Specimens at Elevated Temperatures
This standard is issued under the fixed designation C 1359; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This test method covers the determination of tensile 2.1 ASTM Standards:
strength including stress-strain behavior under monotonic C 1145 Terminology of Advanced Ceramics
uniaxial loading of continuous fiber-reinforced advanced ce- D 3379 Test Method for Tensile Strength and Young’s
ramics at elevated temperatures. This test method addresses, Modulus for High-Modulus Single-Filament Materials
but is not restricted to, various suggested test specimen D 3878 Terminology of High Modulus Reinforcing Fibers
geometries as listed in the appendix. In addition, specimen and Their Composites
fabrication methods, testing modes (load, displacement, or E 4 Practices for Force Verification of Testing Machines
strain control), testing rates (load rate, stress rate, displacement E 6 Terminology Relating to Methods of Mechanical Test-
rate, or strain rate), allowable bending, temperature control, ing
temperature gradients, and data collection and reporting pro- E 21 Practice for Elevated Temperature Tension Tests of
cedures are addressed. Tensile strength as used in this test Metallic Materials
method refers to the tensile strength obtained under monotonic E 83 Practice for Verification and Classification of Exten-
uniaxial loading where monotonic refers to a continuous someters
nonstop test rate with no reversals from test initiation to final E 220 Test Method for Calibration of Thermocouples by
fracture. Comparison Techniques
1.2 This test method applies primarily to advanced ceramic E 337 Test Method for Measuring Humidity with Psy-
matrix composites with continuous fiber reinforcement: uni- chrometer (the Measurement of Wet-and Dry-Bulb Tem-
directional (1-D), bi-directional (2-D), and tri-directional (3-D) peratures)
or other multi-directional reinforcements. In addition, this test E 380 Practice for Use of International System of Units (SI)
method may also be used with glass (amorphous) matrix (the Modernized Metric System)
composites with 1-D, 2-D, 3-D and other multi-directional E 1012 Practice for Verification of Specimen Alignment
continuous fiber reinforcements. This test method does not Under Tensile Loading
directly address discontinuous fiber-reinforced, whisker-
3. Terminology
reinforced, or particulate-reinforced ceramics, although the test
3.1 Definitions:
methods detailed here may be equally applicable to these
composites. 3.1.1 Definitions of terms relating to tensile testing, ad-
vanced ceramics, fiber-reinforced composites as they appear in
1.3 The values stated in SI units are to be regarded as the
standard and are in accordance with Practice E 380. Terminology E 6, Terminology C 1145, and Terminology
D 3878, respectively, apply to the terms used in this test
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the method. Pertinent definitions are shown in the following with
the appropriate source given in parentheses. Additional terms
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- used in conjunction with this test method are defined in 3.2.
bility of regulatory limitations prior to use. Refer to Section 7
for specific precautions.
Annual Book of ASTM Standards, Vol 15.01.
Annual Book of ASTM Standards, Vol 15.03.
1 4
This test method is under the jurisdiction of ASTM Committee C-28 on Annual Book of ASTM Standards, Vol 03.01.
Advanced Ceramics and is the direct responsibility of Subcommittee C28.07 on Annual Book of ASTM Standards, Vol 14.03.
Ceramic Matrix Composites. Annual Book of ASTM Standards, Vol 11.03.
Current edition approved Dec. 10, 1996. Published December 1997. Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C1359
–3
3.2 Definitions of Terms Specific to This Standard: 3.2.12 modulus of toughness [FLL ], n—strain energy per
unit volume required to stress the material from zero to final
3.2.1 advanced ceramic, n—a highly engineered, high-
fracture indicating the ability of the material to absorb energy
performance predominately nonmetallic, inorganic, ceramic
material having specific functional attributes. (See Terminol- beyond the elastic range (that is, damage tolerance of the
material).
ogy C 1145.)
–1
3.2.12.1 Discussion—Themodulusoftoughnesscanalsobe
3.2.2 axial strain [LL ], n—the average longitudinal
referred to as the cumulative damage energy and as such is
strains measured at the surface on opposite sides of the
regardedasanindicationoftheabilityofthematerialtosustain
longitudinal axis of symmetry of the specimen by two strain-
damage rather than as a material property. Fracture mechanics
sensing devices located at the mid length of the reduced
methods for the characterization of CFCCs have not been
section. (See Practice E 1012.)
–1
developed. The determination of the modulus of toughness as
3.2.3 bending strain [LL ], n—the difference between the
provided in this test method for the characterization of the
strain at the surface and the axial strain. In general, the bending
cumulative damage process in CFCCs may become obsolete
strain varies from point to point around and along the reduced
when fracture mechanics methods for CFCCs become avail-
section of the specimen. (See Practice E 1012.)
able.
3.2.4 breaking load [F], n—the load at which fracture
–2
3.2.13 proportional limit stress [FL ], n—the greatest
occurs. (See Terminology E 6.)
stress which a material is capable of sustaining without any
3.2.5 ceramic matrix composite, n—a material consisting of
deviation from proportionality of stress to strain (Hooke’s
two or more materials (insoluble in one another), in which the
law). (See Terminology E 6.)
major,continuouscomponent(matrixcomponent)isaceramic,
3.2.13.1 Discussion—Many experiments have shown that
whilethesecondarycomponent/s(reinforcingcomponent)may
values observed for the proportional limit vary greatly with the
be ceramic, glass-ceramic, glass, metal, or organic in nature.
sensitivity and accuracy of the testing equipment, eccentricity
These components are combined on a macroscale to form a
of loading, the scale to which the stress-strain diagram is
useful engineering material possessing certain properties or
plotted, and other factors. When determination of proportional
behavior not possessed by the individual constituents.
limit is required, the procedure and sensitivity of the test
3.2.6 continuous fiber-reinforced ceramic matrix composite
equipment shall be specified.
(CFCC), n—a ceramic matrix composite in which the reinforc-
3.2.14 percent bending, n—the bending strain times 100
ing phase consists of a continuous fiber, continuous yarn, or a
divided by the axial strain. (See Practice E 1012.)
woven fabric.
–2
3.2.15 slow crack growth, n—sub critical crack growth
3.2.7 fracture strength [FL ], n—the tensile stress that the
(extension) that may result from, but is not restricted to, such
material sustains at the instant of fracture. Fracture strength is
mechanisms as environmentally-assisted stress corrosion or
calculatedfromtheloadatfractureduringatensiontestcarried
diffusive crack growth.
toruptureandtheoriginalcross-sectionalareaofthespecimen.
–2
(See Terminology E 6.) 3.2.16 tensile strength [FL ], n—the maximum tensile
stress which a material is capable of sustaining. Tensile
3.2.7.1 Discussion—In some cases, the fracture strength
strength is calculated from the maximum load during a tension
may be identical to the tensile strength if the load at fracture is
test carried to rupture and the original cross-sectional area of
the maximum for the test.
the specimen. (See Terminology E 6.)
3.2.8 gage length [L], n—the original length of that portion
of the specimen over which strain or change of length is
4. Significance and Use
determined. (See Terminology E 6.)
–2
3.2.9 matrix-cracking stress [FL ], n—the applied tensile
4.1 This test method may be used for material development,
stress at which the matrix cracks into a series of roughly
material comparison, quality assurance, characterization, reli-
parallel blocks normal to the tensile stress.
ability assessment, and design data generation.
3.2.9.1 Discussion—In some cases, the matrix cracking
4.2 Continuous fiber-reinforced ceramic matrix composites
stress may be indicated on the stress-strain curve by deviation
generally characterized by crystalline matrices and ceramic
from linearity (proportional limit) or incremental drops in the
fiber reinforcements are candidate materials for structural
stress with increasing strain. In other cases, especially with
applications requiring high degrees of wear and corrosion
materials which do not possess a linear portion of the stress-
resistance, and elevated-temperature inherent damage toler-
strain curve, the matrix cracking stress may be indicated as the
ance (that is, toughness). In addition, continuous fiber-
first stress at which a permanent offset strain is detected in the
reinforced glass (amorphous) matrix composites are candidate
unloading stress-strain (elastic limit) curve.
materials for similar but possibly less-demanding applications.
–2
3.2.10 modulus of elasticity [FL ], n—the ratio of stress to
Although flexural test methods are commonly used to evaluate
corresponding strain below the proportional limit. (See Termi-
strengths of monolithic advanced ceramics, the non-uniform
nology E 6.)
stress distribution of the flexure specimen in addition to
–3
3.2.11 modulus of resilience [FLL ], n—strain energy per dissimilar mechanical behavior in tension and compression for
unitvolumerequiredtoelasticallystressthematerialfromzero CFCCs leads to ambiguity of interpretation of strength results
to the proportional limit indicating the ability of the material to obtained from flexure tests for CFCCs. Uniaxially-loaded
absorb energy when deformed elastically and return it when tensile-strength tests provide information on mechanical be-
unloaded. havior and strength for a uniformly stressed material.
C1359
4.3 Unlike monolithic advanced ceramics that fracture cata- material performance under use conditions. Monitor and report
strophically from a single dominant flaw, CFCCs generally relative humidity (RH) and temperature when testing is con-
experience 8graceful’ (that is, non-catastrophic, ductile-like ducted in uncontrolled ambient air with the intent of evaluating
stress-strain behavior) fracture from a cumulative damage maximum strength potential.Testing at humidity levels > 65 %
process. Therefore, the volume of material subjected to a RH is not recommended.
uniform tensile stress for a single uniaxially-loaded tensile test
5.2 Surface preparation of test specimens, although nor-
may not be as significant a factor in determining the ultimate
mally not considered a major concern in CFCCs, can introduce
strengths of CFCCs. However, the need to test a statistically
fabricationflawswhichmayhavepronouncedeffectsontensile
significant number of tensile specimens is not obviated. There-
mechanical properties and behavior (for example, shape and
fore, because of the probabilistic nature of the strengths of the
level of the resulting stress-strain curve, tensile strength and
brittle fibers and matrices of CFCCs, a sufficient number of
strain, proportional limit stress and strain, etc.). Machining
specimens at each testing condition is required for statistical
damage introduced during specimen preparation can be either
analysis and design. Studies to determine the influence of
a random interfering factor in the determination of ultimate
specimen volume or surface area on strength distributions for
strength of pristine material (that is, increase frequency of
CFCCshavenotbeencompleted.Itshouldbenotedthattensile
surface-initiated fractures compared to volume-initiated frac-
strengths obtained using different recommended tensile speci-
tures), or an inherent part of the strength characteristics to be
men geometries with different volumes of material in the gage
measured. Surface preparation can also lead to the introduction
sections may be different due to these volume differences.
of residual stresses. Universal or standardized methods for
4.4 Tensile tests provide information on the strength and
surface preparation do not exist. In addition, the nature of
deformation of materials under uniaxial tensile stresses. Uni-
fabrication used for certain composites (for example, chemical
form stress states are required to effectively evaluate any
vapor infiltration or hot pressing) may require the testing of
non-linear stress-strain behavior that may develop as the result
specimens in the as-processed condition (that is, it may not be
ofcumulativedamageprocesses(forexample,matrixcracking,
possible to machine the specimen faces without compromising
matrix/fiber debonding, fiber fracture, delamination, etc.) that
the in-plane fiber architecture). Final machining steps may, or
may be influenced by testing mode, testing rate, effects of
maynotnegatemachiningdamageintroducedduringtheinitial
processing or combinations of constituent materials, environ-
machining. Therefore, report specimen fabrication history
mental influences, or elevated temperatures. Some of these
since it may play an important role in the measured strength
effects may be consequences of stress corrosion or sub critical
distributions.
(slow) crack growth that can be minimized by testing at
5.3 Bending in uniaxial tensile tests can cause or promote
sufficiently rapid rates as outlined in this test method.
non-uniform stress distributions with maximum stresses occur-
4.5 The results of tensile tests of specimens fabricated to
ring at the specimen surface leading to non-representative
standardized dimensions from a particular material or selected
fracturesoriginatingatsurfacesorneargeometricaltransitions.
portions of a part, or both, may not totally represent the
Bending may be introduced from several sources including
strength and deformation properties of the entire, full-size end
misaligned load trai
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