ISO 21713:2020

INTERNATIONAL ISO
STANDARD 21713
First edition
2020-03
Fine ceramics (advanced ceramics,
advanced technical ceramics) —
Determination of elastic modulus of
ceramics at high temperature by thin
wall C-ring method
Céramiques techniques (céramiques avancées, céramiques techniques
avancées) – Détermination du module élastique des céramiques à
haute température par la méthode de l’anneau en C à parois minces
Reference number
ISO 21713:2020(E)
©
ISO 2020

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ISO 21713:2020(E)

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ISO 21713:2020(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 3
5.1 Testing machine . 3
5.2 Heating system . 4
5.2.1 General. 4
5.2.2 Test piece temperature stability . 4
5.2.3 Test temperature uniformity . 4
5.2.4 Furnace heating rate . 4
5.2.5 Furnace stability. 4
5.3 Temperature-measuring and indicating instruments . 4
5.3.1 General. 4
5.3.2 Thermocouples . 4
5.3.3 Verification of the thermocouple temperature-measuring system . 4
5.4 Vacuuming machine . 4
5.5 Data acquisition . 4
5.6 Dimension-measuring device. 5
6 Test pieces . 5
6.1 Test piece size and preparation . 5
6.1.1 General. 5
6.1.2 Test piece storage . 5
6.1.3 Number of test pieces . 5
6.2 Rigid disk preparation . 5
7 Test procedures . 6
7.1 Check of vacuuming system . 6
7.2 Check of heating system . 6
7.3 Testing machine and loading speed . 6
7.4 Elastic modulus measurement steps . 6
7.5 Test validity requirement. 7
8 Calculation of results . 8
8.1 Calculation of the elastic modulus . 8
8.2 Mean value and standard deviation for elastic modulus . 8
9 Test report . 8
Bibliography .10
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ISO 21713:2020(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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This document was prepared by Technical Committee ISO/TC 206, Fine ceramics.
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INTERNATIONAL STANDARD ISO 21713:2020(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Determination of elastic modulus of ceramics
at high temperature by thin wall C-ring method
1 Scope
This document specifies the determination of elastic modulus of ceramics at high temperatures up
to 2 100 °C by using the thin wall relative C-ring method. Procedures for test piece preparation, test
modes, heat rate, load rates, data collection and reporting are given.
This document applies primarily to ceramic materials including monolithic fine ceramics, refractory
materials, whisker and particulate-reinforced ceramic composites. This method is not applicable to
super plastic ceramics or ceramics with high creep rate. This test method can be used for material
research, quality control and characterization and design data generation purposes.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3611, Geometrical product specifications (GPS) — Dimensional measuring equipment: Micrometers for
external measurements — Design and metrological characteristics
ISO 7500-1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1:
Tension/compression testing machines — Calibration and verification of the force-measuring system
IEC 60584-1, Thermocouples — Part 1: Reference tables
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
elastic modulus
ratio of stress to strain, also known as Young's modulus
3.2
C-ring test piece
test piece in the shape of a split ring, prepared by cutting an incision from a thin wall ring
Note 1 to entry: R is the outer radius, r is the inner radius, and b is the width (axial length), as shown in Figure 1.
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ISO 21713:2020(E)

Figure 1 — Schematic diagram of C-ring test piece
3.3
rigid disk
disk which has the same radius and width as the C-ring test piece (3.2), but which is much stiffer
3.4
relative C-ring method
testing method for determining the deformation of the C-ring by comparing the crossbeam
displacements of the C-ring and the rigid disk under same testing conditions
4 Principle
At ambient temperature, install a C-ring test piece on the fixture and keep the notch at the middle
height. Place the fixture on the flat anvil of a mechanical testing machine and apply a symmetrically
compressive load, F, on the C-ring within its range of elasticity, as shown in Figure 2 a) and b). There
is a linear relationship between the load increment, ΔF, and the displacement increment, Δδ. The
compressive deformation of the C-ring can be directly measured by an accurate inductance micrometer
or any other displacement meter at room temperature. The elastic modulus can be obtained from the
load-deformation curve and the test piece dimensions.
a)  C-ring b)  Deformed C-ring under c)
...