ISO 14574:2013

Overview - ISO 14574:2013 (Tensile testing of ceramic matrix composites at high temperature)

ISO 14574:2013 specifies procedures for determining the tensile properties of ceramic matrix composites (CMC) with continuous fibre reinforcement at temperatures up to 2 000 °C. The standard applies to unidirectional (1D), bi‑directional (2D) and tri‑directional (xD, 2 < x ≤ 3) CMCs loaded along a principal reinforcement axis. It defines test conditions, specimen preparation, apparatus requirements, measurement methods and result reporting for high‑temperature tensile testing of fine/advanced ceramics.

Key topics and technical requirements

• Scope & materials: Ceramic matrix composites with continuous fibres; intended for tensile tests in oxidizing environments (note: not a method for measuring oxidation).
• Test principle: Specimens heated to test temperature and loaded in tension while recording force and longitudinal deformation; tests may use constant crosshead displacement, constant deformation rate, or constant loading rate.
• Temperature control: Tests to be performed at temperatures up to 2 000 °C; controlled temperature zone must include the gauge length and meet the standard’s temperature uniformity requirements (temperature gradient within the gauge length ≤ 20 °C; control tolerance specified for the controlled zone).
• Apparatus & measurement:
  • Test machine force measurement conforming to ISO 7500‑1 (grade 1 or better).
  • Gastight test chamber with controlled atmosphere or vacuum; atmosphere and pressure chosen according to material and temperature.
  • Load‑train and grip design to avoid bending or torsion; options include hot grips (inside hot zone) or cooled grips (outside hot zone).
  • Extensometry: mechanical or electro‑optical extensometers capable of continuous high‑temperature strain measurement; linearity tolerance < 0.05% of the extensometer range.
• Specimen and data: Definitions and calculation methods for initial, apparent and effective cross‑section areas; tensile strength (apparent/effective), strain at maximum force, and proportionality ratio / pseudo‑elastic modulus.
• Test validity & reporting: Requirements for alignment verification, number of specimens, test duration (to limit creep effects), and the content of the test report.

Practical applications

• Characterizing tensile performance of CMCs used in aerospace, power generation (gas turbines), thermal protection systems, and other high‑temperature structural components.
• Supporting R&D, material selection, quality control and design validation where materials operate near or above conventional ceramic temperature limits.
• Informing design allowances, life prediction, and comparisons between fibre architectures (1D, 2D, xD).

Who should use this standard

• Materials scientists and test laboratories performing high‑temperature mechanical characterization.
• Manufacturers of advanced ceramics and CMC components.
• Engineers in aerospace, energy, and industrial sectors requiring validated tensile data for high‑temperature design.

Related standards and references

• ISO 7500‑1 (force measurement calibration for testing machines)
• ISO 3611 (micrometer characteristics)
• IEC 60584‑1 / IEC 60584‑2 (thermocouples) Using ISO 14574:2013 ensures consistent, reproducible tensile data for high‑temperature ceramic composites and supports reliable material qualification and component development.