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ECSS-E-HB-32-20_Part6A(20March2011)-page=329 | ECSS-E-HB-32-20_Part6A(20March2011) | ECSS‐E‐HB‐32‐20 Part 6A
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74.12.1.4 Reflective coating quality
Cracks, poor adherence and poor coverage occurred in thick (>50μm) PECVD‐SiO2 coatings.
PECVD‐SiC coatings 200μm thick were deposited on substrate samples (60mm x 100mm). These
showed the presence of cracks after polishin... | {
"document_id": "ECSS-E-HB-32-20_Part6A(20March2011)",
"page_number": 329
} | null |
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Figure 74.12‐3 – Coatings: Dimensionally stable carbon‐carbon – Manufacturing
method
74.13 References
74.13.1 General
[74‐1]
ʹAdvanced Surface Coatings: A Handbook of Surface Engineeringʹ
Editors: D.S. Rickerby & A. Matthews. Chapman and Hall
ISBN 0‐412‐02541‐8, 19... | {
"document_id": "ECSS-E-HB-32-20_Part6A(20March2011)",
"page_number": 330
} | null |
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[74‐8]
M.F. Gruninger & M.V. Boris
ʹThermal Barrier Ceramics for Gas Turbine and Reciprocating Heat
Engine Applicationsʹ
Proceedings of the International Thermal Spray Conference & Exposition,
Orlando, 28 May ‐ 5 June 1992, p487‐492
[74‐9]
H. Lammermann & G. Kienel
... | {
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"page_number": 331
} | null |
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ʹPlasma Spraying Deposition of Graded Thermal Barrier Coatingsʹ
Proceedings of the International Thermal Spray Conference & Exposition,
Orlando, 28 May ‐ 5 June 1992, p525‐530
[74‐21]
J. Verrier et al
ʹImprovements in Thermal Barrier Coatings for Gas Turbine
Component... | {
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"page_number": 332
} | null |
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[74‐30]
A.N. Gordeev et al
ʹAn Induction Plasma Application to BURANʹs Heat Protection Tiles
Ground Tests: Part Iʹ
SAMPE Journal Vol.28, No.3, May/Jun 1992, p29‐33
[74‐31]
A.N. Gordeev & M.I.Yakushin
ʹThe Thermochemical Stability of Carbon‐Carbon using an Anti‐oxidat... | {
"document_id": "ECSS-E-HB-32-20_Part6A(20March2011)",
"page_number": 333
} | null |
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75
Seal technology
75.1 Introduction
75.1.1
Uses
Seals are used in the assembly of components involved with fluid flow or pressure, for both static and
dynamic environments. Their functions differ greatly in terms of:
Loads (static and dynamic).
Temperature pe... | {
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"page_number": 334
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75.1.3
Dynamic seals
Dynamic seals, as found with rotating shafts, are not included in this chapter, with the exception of
some reference documents, Ref. [75‐1], [75‐2].
Silicon carbide is a particularly good dynamic seal material that can operate at high temperatures.... | {
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"page_number": 335
} | null |
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75.3 Seal materials
75.3.1
General
Seal applications are demanding and materials selection is generally based on material forms with a
proven, predictable performance.
Nickel alloys and ceramic‐based seals are used in high‐temperature applications. Some gra... | {
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"page_number": 336
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incompressibility is the result of the very high ratio between their high bulk modulus, and the low
shear modulus. A common misconception is that the incompressibility is due to their having a
Poisson’s ratio very close to 0.5. In fact, this is onl... | {
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"page_number": 337
} | null |
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The large potential deformations in elastomers can occur because, under stress, these highly‐kinked
molecules are able to straighten out, perhaps to several times the kinked length. The chainlike
molecules themselves are highly flexible and offer litt... | {
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"page_number": 338
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75.3.3
Types of elastomers
75.3.3.1
Formulation
An engineering elastomer is a chemically and physically bonded composition of several ingredients,
vulcanised (‘cured’) together, usually with the application of pressure and heat in a suitably shaped
mould. Broadly the ... | {
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Table 75.3‐2 – Elastomers: Summary of common materials and characteristics
Material (1)
Comments
Natural rubber
(NR) (1)
High-strength, general purpose rubber. The high strength derives
mainly from its ability to crystallise partially under strain.
Chloroprene rubber... | {
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Figure 75.3.3 shows that the tensile strengths at 23°C have almost halved at 100°C. Even at 100°C,
which is at or near the highest practicable service temperature for natural rubber, it is still stronger
than the heat‐resistant rubbers at 23°, and still maint... | {
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"page_number": 341
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The solubility parameter of a mixture of two (or more) miscible liquids is different from the solubility
parameters of the individual components. Thus a rubber can swell in a mixture of two liquids, even
though it does not swell in either of them alone. Other factors can ... | {
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"page_number": 342
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In the long term, temperature cycling does not increase the total amount of sealing force lost, but it
occurs more quickly.
[See: ECSS‐Q‐70‐71; ECSS‐Q‐ST‐ST‐70‐04]
75.3.3.7
Radiation
Much work has been done on the effects of both non‐ionizing and ionizing radiation on ... | {
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Stress
Strain
Extension
Retraction
Figure 75.3‐4 – Elastomers: Viscoelasticity – hysteresis effect
For many practical purposes in engineering design the non‐elastic effects are ignored, so that, for
example, a ‘modulus’ is quoted which enables the calculat... | {
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"page_number": 344
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75.3.5.2
Hardness and elastic modulus
The hardness of an elastomer is usually the first physical characteristic described, e.g. 75 hard nitrile
rubber sealing ring. The hardness is measured by a special instrument with a spherical indentor which
pushes into the rubbe... | {
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"page_number": 345
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75.3.5.4
Tear strength
Fatigue due to repeated stressing is a common mode of ultimate failure in components. A parameter
known as tearing energy is used in calculations related to such failure, and this can be measured in the
laboratory by tear testing.
A commonly used... | {
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'
"
tan
G
G
[75.3‐3]
Where:
G’ :
the in-phase or elastic component of the shear stress, known as the storage
modulus.
G’’ :
the out-of-phase or viscous component of the shear stress, known as the loss
modulus.
The absolute value of the complex modulus, G... | {
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"page_number": 347
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75.3.5.6
Compression set
Compression set is a measure of the lack of recovery of the original dimensions of a rubber component
which has been held in a deformed state for some time.
The original purpose of the test was to ensure that rubbers are fully vulcanised. If a m... | {
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"page_number": 348
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At normal ambient temperatures, creep and stress relaxation are predominantly physical phenomena,
associated with rearrangement and slippage of the molecular network under stress. There can also be
chemical components to creep and stress relaxation when chemicals ... | {
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Figure 75.3‐5 – Elastomers: Creep of a weighted rubber strip
Figure 75.3‐6 – Elastomers: Creep of a weighted rubber strip (logarithmic time)
Figure 75.3.6 shows that the plot is now linear, which is always approximately the case for plots of
physical creep or stres... | {
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"page_number": 350
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75.3.6
Chemical properties
75.3.6.1
Heat resistance
Degradation of elastomers at elevated temperatures is usually oxidative.
Oxidation is a chemical reaction, and as such the rate approximately doubles for each 10°C rise in
temperature. Oxidation rates, however, are ... | {
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heat resistance and physical properties – need to be carefully balanced. Model tests, and the use of
past experience, can be needed in order to optimise selection.
75.3.6.2
Low temperature resistance
The effects which low temperatures have on the stiffness and resilienc... | {
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75.3.6.3
Chemical resistance
Chemical degradation of an elastomer can be caused by a number of agents, including:
Oxidation in air, particularly at higher temperatures.
Hydrogen sulphide gas.
Liquids, of which many are detrimental, e.g. ionic attack by amines ... | {
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"page_number": 353
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Figure 75.3‐8 – Elastomers: Arrhenius plot example
The creep rate at 23°C can be read from the graph (antilog of –16.5 i.e. 6.8 10‐6 % per minute). The
total creep at room temperature for any given time can then be calculated.
Arrhenius plots are a useful way ... | {
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"page_number": 354
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75.3.8
Engineering design with elastomers
75.3.8.1
Fundemental aspects
Elastomers are rarely used in tension in engineering applications. Most components operate in shear
or compression or a combination of the two, occasionally in torsion or bending.
Except for seals... | {
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Where:
Ec: compression modulus.
A: the cross sectional area.
t: thickness
The compressive modulus is not just a material property, but is dependent on both the intrinsic
stiffness of the rubber and the shape of the block.
Rocard first described com... | {
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"page_number": 356
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A more detailed treatment of the compression stiffness of blocks can be found in Ref. [75‐16].
75.3.8.4
Compression stiffness of laminated blocks
Laminated rubber blocks comprise a number of discrete rubber layers divided by horizontal metal
plates to which the rubber i... | {
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D
d
t
Figure 75.3‐11 – Elastomers: Elastomeric torsion disc
The torsional stiffness is given by:
4
4
32
d
D
t
G
T
K
[75.3‐18]
Where:
T: torque,
: angular rotation in radians,
G: shear modulus as before,
t: thickness,
D: outer diamete... | {
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Given the high strains involved, the material model is called a ‘hyperelastic model’. The input from
the laboratory tests are used in the FEA program to generate the coefficients for the chosen
mathematical strain energy density model. FEA analysis can then... | {
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"page_number": 359
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75.3.10 Applications
75.3.10.1 General
Industrial, general engineering and aerospace applications for elastomers are similar. Some typical
examples include:
Vibration isolation, e.g. anti‐vibration mounts,
Seals, such as O‐rings and gaskets, [See: 75.... | {
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"page_number": 360
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knowledge of possible causes of leakage, e.g.
temperature,
pressure,
changes in fluids.
explosive decompression; also known by rubber technologists as ‘rapid gas
decompression’.
75.3.11 Thermoplastic elastomers
As well as the wide range of vul... | {
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"page_number": 361
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Figure 75.4‐1 ‐ Metal seals: ʹCʹ profile and serpentine
75.4.2
Materials
Appropriate materials include:
Nimonic 90,
Inconel X‐750,
Inconel 718, and
Elgiloy.
Seals made from these alloys are expected to retain their spring capacity up to 800°C. | {
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"page_number": 362
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75.5 NASP engine developments
75.5.1
General
The development of the NASP engine is an example of advanced high‐temperature seal technology,
Ref. [75‐5], [75‐6].
NASP is reliant on a hydrogen‐burning hypersonic engine, [See: 73.10].
Designs similar to turbojet no... | {
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"page_number": 363
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75.5.2.2
Braided Ceramic Rope Seal
Figure 75.5.2 shows that the ceramic wafers can be replaced by a braided rope, Ref. [75‐5]. This is
formed of alumina‐boria‐silicate (Nextel) fibres capable of sustaining 1260°C. In high heat flux
environment... | {
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"page_number": 364
} | null |
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75.7 Elastomeric seals
75.7.1
Materials
75.7.1.1
General
Elastomers are widely used in sealing applications because they are both soft and resilient. In many
cases, there is no alternative material that can be used.
The choice of elastomer for a particular seal is us... | {
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75.7.3
Causes of leakage
75.7.3.1
Static seals
Static seals, when designed competently, rarely leak in continuous use. Leakage almost always follows
a change in conditions at the seal, e.g.
temperature change,
pressure change,
change in composition of the... | {
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"page_number": 366
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75.7.3.5
Changes in fluids
Where the nature of the sealed fluid changes during the service life problems can occur. For example:
when the UK national gas supply changed in composition the replacement gas had a smaller swelling
effect on the seals. Contraction of the sea... | {
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"page_number": 367
} | null |
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Aerospace can, however, have much greater applications demands than are usual, e.g. higher
temperatures, wider temperature extremes, very high chemical resistance, high purity to avoid
contamination.
[See: ECSS‐Q‐70‐71]
75.8 References
75.8.1
... | {
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"page_number": 368
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Plastics, Rubber and Composites Processing and Applications
Vol
26 No 3, p.129‐36, 1997
[75‐11]
S.D. Gehman & T.C. Gregson
‘Ionizing radiation and elastomers’
Rubber Chemistry and Technology Vol 33, p.1375‐1437, 1960
[75‐12]
S.G. Burnay & J.W. Hitchon
‘Predicti... | {
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"page_number": 369
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ECSS‐Q‐ST‐70‐06
Particle and UV radiation testing of space
materials
75.8.3
ASTM standards
[See: ASTM website]
ASTM E595
Standard test method for total mass loss and
collected volatile condensable materials from
outgassing in a vacuum environment
75.8.4
ISO sta... | {
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76
Integrity control of high temperature
structures
76.1 Introduction
Integrity control is applied to fibre‐reinforced composite materials. It determines the requirements for
those materials which exhibit failure or fracture characteristics very different from those of... | {
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"page_number": 371
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76.2.2
Fracture control
For materials whose behaviour can be predicted by fracture mechanics, the term ‘Fracture Control’ is
used.
[See: ECSS‐E‐ST‐32‐01]
To date, these include some particulate‐reinforced materials, some whisker‐reinforced materials and
the advance... | {
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76.4 High temperature
Operation at high temperatures means that the material systems used are likely to undergo
microstructural changes, as well as experiencing mechanical or thermal loading damage and surface
environmental attack.
Therefore another aspe... | {
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For MMC and CMC materials, which achieve their damage tolerance by controlled instigation and
propagation of ʹdefectsʹ, determining realistic acceptance levels is complicated by the inherent
inhomogeneity of the material and by the fact that material ... | {
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Table 76.6‐1 ‐ Integrity control parameters for new materials
Technology stage
Tasks
Material availability:
appropriate forms and quantity
raw materials, with fixed specifications & quantity
second source of equivalent material
Fabricate:
demonstrator (d... | {
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Figure 76.7‐1 ‐ Integrity control for high‐temperature applications: Study logic
Figure 76.7‐2 ‐ Integrity control for high temperature applications: Approach | {
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76.8 Case study: Phase 1 - Material characterisation
76.8.1
General
Phase 1 (1992‐93) broadly considered the:
ability of selected NDI methods to detect anticipated manufacturing defects and thermally
induced damage, and
proportion of maximum strength... | {
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The basic assumption was that manufacturing defects introduced at the polymer composite moulding
stage cannot be rectified by any subsequent infiltration and pyrolysis steps.
76.8.3
Defect detection by selected NDI methods
76.8.3.1
General
It was recognised in adv... | {
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76.8.3.5
Unsuccessful techniques
X‐ray microfocus technique for better resolution proved unreliable and time consuming.
IR thermography showed some success in revealing delaminations in C‐SiC and SiC‐SiC, but
the conductivity of C‐C was too high.
An automated t... | {
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76.8.5
High-temperature tests
76.8.5.1
Test regime
The specimens underwent limited thermal cycling (1 to 4 cycles) superimposed on dynamic (0.5Hz)
mechanical loading.
The basic loading and temperature regimes within a single cycle were:
C‐SiC and SiC‐SiC:
Hea... | {
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76.8.6
Residual strengths
76.8.6.1
SiC-SiC
The material shows good strength retention after 1 to 4 thermo‐cycles with μmax = 87MPa at
1100°C.
NDT revealed a significant increase in matrix microcracking throughout the specimens.
76.8.6.2
C-SiC
... | {
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76.9 Case study: Phase 2 - Structural sub-component
behaviour
Phase 2 (1993‐94) undertook:
Evaluation of a winged launcher C‐SiC shingle,
Development of analysis tools for structural parts,
Acoustic noise tests,
Continuation of thermo‐mechanical testing, b... | {
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77
Defect types
77.1 Introduction
No material is free from flaws. Likewise all structures contain defects and may experience damage
during operational use, either by the propagation of existing defects or by accident. Depending on the
type of material and the processin... | {
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77.2 Advanced metal alloys
77.2.1
General
In general, where property improvements do not cause pronounced anisotropy, material defects
similar to those of traditional metal alloys can occur, e.g.:
Inclusions,
Pores,
Cracks,
Contamination, ... | {
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77.3.3
Near-net shape manufacture
For materials manufactured simultaneously with the part, Table 77.3.1 lists potential defects and their
possible causes, Ref. [77‐1].
Table 77.3‐1 ‐ MMC: Typical material defects
Defect
Possible cause
Reinforcement
Incorrect lay-up.... | {
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77.4 Ceramic matrix composites
The integrity of CMCʹs is determined by the reinforcement, matrix and interface acting together. The
defect types listed in Table 77.4.1 apply to ceramic, glass and carbon matrix composites, Ref. [77‐2] to
[77‐6].
Table 77.4‐1 ‐ CMC: Typic... | {
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Table 77.5‐1 ‐ Coating materials: Typical defects
Defect
Possible cause
Mis-location.
Thickness variations.
Process and part geometry.
Cracks:
Surface breaking.
Within coating.
CTE mismatch between substrate & coating.
Residual stresses from:
Process: Temperatur... | {
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Table 77.6‐1 ‐ Fusion joints: Example of techniques and use
Technique
Comments
Welding
Weldable metals.
Brazing
Dissimilar or similar.
Metallic
Diffusion bonding
Either with SPF, or secondary
joining.
Brazing
Dissimilar or similar.
Ceramic
Bonding
Example: by... | {
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77.7 Structural parts
77.7.1
General
Defects occurring during the manufacture of parts can be classed as those occurring from further
processing of materials:
Metal alloys,
Composite materials: e.g. bought‐in or near‐net shape manufacture.
77.7.2 ... | {
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Table 77.8‐1 ‐ Typical in‐service defects
Defects
Comments
Metallic
Cracks.
Initiation at surfaces or internal defects. Propagation by thermal or
mechanical cyclic loads.
Residual stress.
Microstructure.
Temperature induced changes.
MMCʹs
Cracks.
Matrix fatigue ... | {
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77.9 References
77.9.1
General
[77‐1]
W.N. Reynolds: AERE‐Harwell, UK
ʹNon destructive Testing Techniques for Metal Matrix Compositesʹ
AERE‐R 13040 (June 1988)
[77‐2]
A. Morsh et al: Fraunhofer‐Institute for NDT, Germany
ʹRecent Progress in High Frequency Ultrasoni... | {
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78
Damage tolerance
78.1 Introduction
78.1.1
Materials
Damage tolerance is the ability of a material to retain an acceptable level of structural and or
environmental resistance properties under the effects of operational conditions, without risk of fai... | {
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For conventional materials a direct assessment of damage tolerance can be made on relative crack
velocity against stress intensity behaviour. The intrinsic Initial Material Quality (IMQ), defined as a
distribution of microstructural anomalies that might lead... | {
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Figure 78.2‐1 ‐ Whisker and particle reinforced MMC: Fatigue response
78.2.1.2
Particulate size
The size of particle used can strongly influence fatigue performance and fracture toughness, as
summarised in Table 78.2.1, Ref. [78‐3].
Therefore there exist... | {
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78.3 CMC: Whisker reinforced
Little information on the performance of whisker‐reinforced ceramics is, as yet, openly published.
A study, Ref. [78‐4], to examine the high‐temperature performance of SiC whisker‐reinforced alumina
demonstrated that for chevron‐notched test... | {
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Figure 78.4‐2 ‐ Failure modes of MMC
78.4.1.2
Single crack failures
Single crack failure, also known as self‐similar crack growth, occurs when the fatigue failure strains
for matrix and fibre are similar, i.e.:
when interfacial bonding is high (too high), and
... | {
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Figure 78.4‐3 ‐ MMC: Fatigue response showing matrix failure
There are three regions, [See: Figure 78.4.3]:
Shakedown: Plastic deformation can occur during the first few cycles as the composite responds
to loading. The ‘Shakedown Stress’ is reached if the matrix cyc... | {
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temperature at which the matrix is infiltrated, can cause significant fibre‐matrix reactions at the
interface. Consequently the overall ʹidealisedʹ fibre properties are never realised in a consolidated
composite.
78.5.1.3
Fracture characterisati... | {
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These factors are influenced by operation in hostile environments, e.g.:
High temperature,
Thermal cycling,
Erosion,
Atmospheres, such as:
oxygen, and
hydrogen.
Application of a coating can influence the overall mechanical properties of the su... | {
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78.7 References
78.7.1
General
[78‐1]
T.E. Farmer & M.C.VanWanderham: Pratt & Whitney, (USA)
ʹDamage Tolerance Concepts for Advanced Materials & Enginesʹ
AGARD‐CP449‐Application of Advanced Materials for Turbo‐machinery
& Rocket Propulsion, p6‐1 to 6‐7
[78‐2]
MIL‐... | {
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79
Fracture control
79.1 Introduction
79.1.1
Application
79.1.1.1
Alloys
Fracture control is applied to materials which can be adequately predicted by Fracture Mechanics
principles; [See: ECSS E‐ST‐32‐01, previously ESA PSS‐01‐401].
In general, this ap... | {
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80
NDT techniques
80.1 Introduction
Various NDI techniques are evolving from the established methods for the inspection of advanced
material systems for high‐temperature applications. The impetus is to detect defects in brittle
materials that are smaller... | {
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post‐manufacture because, in many cases, the geometry inhibits access. Fewer still have potential for
in‐service use.
For in‐service inspection, ideally a technique is non‐contact, automated, remote (for external surfaces)
and with access to the part (internal st... | {
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Table 80.3‐1 ‐ NDI techniques for MMCs
Technique
Ultrasonic
Defect or
measurement
Velocity
C‐scan
Stress
wave
Radio‐
graph
y
Acoustic
emission
Thermo‐
graphy
Eddy
curren
t
Electric DC
resistivity
Reinforcement content:
Particulate
... | {
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Table 80.4‐1 ‐ NDI techniques for defect detection and measurement of C‐C and
CMC materials
NDI METHOD
X-ray
Ultrasonic (2)
IR Thermo-
graphy
Micro- wave
DEFECT DETECTION
or
MEASUREMENT CAPABILITY
Radiography
Microfocus
Tomography
Backscatter
LF Transmission
HF Transmissi... | {
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Table 80.4‐2 ‐ Technical and economical aspects of NDI techniques
Possibility of NDI technique for:
NDI
method
Investment
cost
Speed
Maintenance
Real‐time
On‐line
Full
automation
Quantitative
Safety
requirement
Availability
X‐ray:
Radiogra... | {
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80.5 Coatings
Table 80.5.1 summarises techniques for coating inspection. The technique used varies with the
particular material system. For details of equipment configuration, see the cited reference.
Table 80.5‐1 ‐ Coatings: Inspection techniques
Coating sy... | {
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80.6.3
Mechanically fastened and interlock joints
80.6.3.1
TPS structures
Considering the important role of TPS to the overall vehicle safety, every method used should be
capable of ensuring that the connection is viable for further service, [See also: C... | {
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80.7.2
Thin-walled seam welded tubes
Examples of standards which exist for the inspection of high‐reliability condenser tubes are given in
Table 80.7.2, Ref. [80‐15].
Table 80.7‐2 ‐ Standards for inspection of welded tubes
NDT Technique
Standard (1) (2)
ASTM B338
Ed... | {
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ISBN 87762‐700‐2‐60 p223‐232
[80‐3]
W.N. Reynolds: AERE Harwell, (UK)
ʹNon‐destructive testing Techniques for Metal Matrix Compositesʹ
AERE‐R 13040 June 1988
[80‐4]
W.S. Johnson: NASA‐Langley Research Center, (USA)
ʹScreening of Metal Matrix Composites using Ultras... | {
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ʹThermographic Inspection of Superplastically Formed Diffusion Bonded
Titanium Panelsʹ
SPIE Vol.934: Thermosense X (1988) p102‐110
[80‐14]
D.A Hutchins et al: Queens University, Ontario, Canada
ʹNon‐contact Ultrasonic Inspection of Diffusion Bonds in Titaniumʹ
Ultraso... | {
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81
High-temperature testing
81.1 Introduction
Background information on the testing of advanced metallic and ceramic materials at high
temperatures is provided. The response of materials to aggressive high‐temperature environments is
complex, with a range o... | {
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residual properties after mechanical loading, thermal exposure and hot corrosion, e.g. thermo‐
mechanical fatigue (TMF).
Residual property measurement, which covers all degradation processes, is a better measurement of a
materialʹs capabilities. It determines the val... | {
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81.4 Degradation mechanisms
81.4.1
Materials
81.4.1.1
Metal compositions
Possible degradation mechanisms listed in order of occurrence and ultimate severity are:
Change in microstructure,
Grain growth,
Brittle phase formation, including hydrogen embrittleme... | {
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81.5 Coupon testing
81.5.1
General
Measurement of the mechanical and physical properties of metallic and ceramic‐based composite
materials from test coupons has the difficulty of interpreting this data for bulk material properties or
net‐shape components. Co... | {
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"page_number": 415
} | null |
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81.5.6
Small coupon tests
The quantities of MMC and CMC materials prepared for net‐shape applications can be small. This,
combined with the complexity of the component or processing route, e.g. extrusion or CVI, makes
small test coupons necessary.
A good understanding... | {
"document_id": "ECSS-E-HB-32-20_Part6A(20March2011)",
"page_number": 416
} | null |
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Figure 81.5‐1 ‐ Coupon testing: Scanning laser extensometry system
81.5.9
End tabs
For high‐temperature tensile testing, problems in gripping the coupon can be solved by using a long
specimen with a hot gauge length and two cooled ends within the grips. This enables m... | {
"document_id": "ECSS-E-HB-32-20_Part6A(20March2011)",
"page_number": 417
} | null |
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81.5.12 Specimen alignment
With high modulus and low strain materials, specimen alignment within loading jigs is essential if the
tests are to be representative. In tensile and compressive loading, bending moments are minimised.
81.5.13 Linear elasticity
Most MMCs and... | {
"document_id": "ECSS-E-HB-32-20_Part6A(20March2011)",
"page_number": 418
} | null |
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81.6.2
Tensile
81.6.2.1
General
The measurement of properties at ambient temperature eliminates the problem of temperature effects,
not least because bonded aluminium tabs can be used. Agreement is usually possible on initial
modulus measurement due to t... | {
"document_id": "ECSS-E-HB-32-20_Part6A(20March2011)",
"page_number": 419
} | null |
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Figure 81.6‐1 ‐ CMC high temperature tensile testing: CEN recommended sample
types
ASTM D 3552‐77(1985) describes measurement of tensile properties for fibre‐reinforced metal matrix
composites, [See also: Chapter 7].
Linear regression computer analysis is gaining prom... | {
"document_id": "ECSS-E-HB-32-20_Part6A(20March2011)",
"page_number": 420
} | null |
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421
configurations. This implies a simple tensile loaded test with a straight edge ±45° coupon, as applied
to fibre‐reinforced plastics in ASTM D 3518.
As many CMC materials use fabrics, the simple system needs evaluation as to its applicability.
81.6.5
Open-hole tension
T... | {
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"page_number": 421
} | null |
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81.8 Physical properties
81.8.1
General
For high‐temperature applications, physical properties concerned in heat management are very
important. They are quantified over representative temperature ranges for the application. Emphasis
is placed on:
Thermal ... | {
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"page_number": 422
} | null |
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81.9.2
Metal matrix composites
The ASTM D‐30 and E‐8 committees are responsible for a range of test methods appropriate to MMC
materials.
VAMAS has a Technical Working Area (TWA) on MMC materials, including a ‘round‐robin’ test
programme on particulate‐re... | {
"document_id": "ECSS-E-HB-32-20_Part6A(20March2011)",
"page_number": 423
} | null |
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reinforcement characterisation methods, e.g. strength and thermophysical properties.
The standards listed cover reinforced ceramics with continuous ceramic or carbon fibres, where the
reinforcement can be:
unidirectional, in‐plane, i.e. reinforcement placed in at... | {
"document_id": "ECSS-E-HB-32-20_Part6A(20March2011)",
"page_number": 424
} | null |
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Table 81.9‐1 ‐ Test methods: CEN standards for advanced technical ceramic
composites
Title
Standard
No.
General:
Notations and symbols
ENV
13233
Mechanical properties at RT:
Mechanical properties of ceramic composites at room temperature – Part 1:
Determinati... | {
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"page_number": 425
} | null |
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Reinforcements:
Ceramic composites – Methods of test for reinforcements – Part 4:
Determination of tensile properties of filament at ambient temperature
ENV 1007-
4
Ceramic composites – Methods of test for reinforcements – Part 5:
Determination of distribution of ten... | {
"document_id": "ECSS-E-HB-32-20_Part6A(20March2011)",
"page_number": 426
} | null |
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Table 81.9‐3 ‐ Test methods: CEN standards for advanced technical ceramics ‐
coatings
Title
Standard
No.
Monolithic of test for ceramic coatings –Part 1: Determination of coating
thickness by contact probe profilometer
ENV 1071-
1
Monolithic of test for ceramic coat... | {
"document_id": "ECSS-E-HB-32-20_Part6A(20March2011)",
"page_number": 427
} | null |
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81.11 References
81.11.1 General
[81‐1]
R. Morrell & L.N. McCartney
ʹMeasurement of Properties of Brittle Matrix Compositesʹ
Br. Ceram. trans., 92, 1993, No. 1, p1‐7
[81‐2]
D.P. Bashford & R. Raynal
ʹTesting and Integrity of Thermostructural Ceramic Compositesʹ
Int... | {
"document_id": "ECSS-E-HB-32-20_Part6A(20March2011)",
"page_number": 428
} | null |
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