Overview
ISO 18610:2016 - "Fine ceramics (advanced ceramics, advanced technical ceramics) - Mechanical properties of ceramic composites at ambient temperature in air atmospheric pressure - Determination of elastic properties by ultrasonic technique" - specifies an ultrasonic, non‑destructive method to determine the components of the elasticity tensor of ceramic matrix composites at room temperature. From the measured tensor components the standard enables calculation of Young’s moduli, shear moduli and Poisson’s ratios for materials with continuous fibre reinforcement (unidirectional, bidirectional and tridirectional) that have at least orthotropic symmetry and known symmetry axes.
Key technical topics and requirements
- Material scope: Ceramic matrix composites (continuous fibre reinforcement: 1D, 2D, ×D with 2 < × ≤ 3) with orthotropic symmetry.
- Measurement principle: Immersed specimen between transmitter and receiver in a coupling fluid (e.g., water); measure time‑of‑flight of quasi‑longitudinal (QL) and quasi‑transverse (QT) refracted waves to determine propagation velocities.
- Instrumentation: immersion tank with temperature control, probe/holder assembly, ultrasonic probes (transducers), pulse generator, signal display/recording (digital oscilloscope) and processing software.
- Test procedures: specimen preparation (thin, plane‑parallel faces), choice of transducer frequency (limited by condition that ultrasonic wavelength > representative elementary volume thickness), reference measurement without specimen, angle‑of‑incidence scanning, density and thickness determination.
- Calculations and outputs: delay, phase velocities, refracted angles, identification of stiffness tensor components Cij, polar velocity plots, quadratic deviation and confidence intervals, conversion to engineering constants (E, G, ν).
- Validity and reporting: measurement validity criteria, reliability checks for identified Cij components and prescribed test report content.
- Normative references: ISO 3611, ISO/IEC 17025, EN 1389 are cited for dimensional metrology, laboratory competence and density/porosity determination.
Practical applications and users
- Materials characterization and R&D for advanced ceramics and ceramic matrix composites.
- Quality control in manufacturing of fibre‑reinforced ceramic components.
- Design verification where accurate elastic constants are required for finite element modelling or structural analysis.
- Accredited testing laboratories and research institutions performing non‑destructive evaluation (NDE).
- Suppliers and OEMs in aerospace, energy, automotive and defense sectors where ceramic composites are used.
Benefits include a non‑destructive route to obtain full elastic tensors at ambient conditions and derived engineering constants. Note the method’s limitation: results may not be directly comparable to values obtained by mechanical test standards (e.g., ISO 15733, ISO 20504, EN 12289) and are subject to wavelength/frequency restrictions.
Related standards