ISO 15733:2015

Overview

ISO 15733:2015 specifies how to determine the tensile properties of ceramic matrix composites (CMCs) with continuous fibre reinforcement at ambient temperature in air (atmospheric pressure). Applicable to unidirectional (1D), bi‑directional (2D) and tri‑directional (xD, 2 < x ≤ 3) reinforcement architectures, the standard defines test principles, specimen geometries, apparatus requirements and result calculation methods for measuring tensile strength, strain, and proportionality/pseudo‑elastic modulus of fine/advanced ceramics and ceramic composites.

Keywords: ISO 15733:2015, ceramic matrix composites, tensile properties, fine ceramics, tensile testing.

Key Topics and Requirements

• Scope and material types: Applies to CMCs with continuous fibres loaded along a principal reinforcement axis; notes common use of antioxidation coatings for high‑temperature service.
• Test principle: Tensile loading at constant crosshead displacement rate or constant strain rate; simultaneous measurement of force and longitudinal deformation.
• Apparatus:
  • Force measurement conforming to ISO 7500‑1 (grade 1 or better).
  • Load train and grips that ensure alignment and prevent bending/torsion.
  • Extensometer suitable for small deformations (mechanical class ≤ 2 per ISO 9513) or electro‑optical systems with appropriate marking.
  • Calibrated digital data recording and micrometers per ISO 3611.
• Specimen types and preparation:
  • Several specimen geometries (Type 1 reduced‑section, Type 2 straight‑sided for modulus, Type 3 with tabs) with recommended dimensions, tolerances and machining/inspection practices.
  • Guidance on as‑fabricated vs machined specimens, gauge length, and representative volume in gauge region.
• Test procedure and data:
  • Mounting, extensometer placement, displacement rates, measurement of dimensions, validity criteria.
  • Calculations for tensile strength, effective tensile strength (accounting for coatings), strain at maximum force, and proportionality ratio/pseudo‑elastic modulus.
• Reporting: Required test data, specimen origin, and calculated results to ensure reproducibility and traceability.

Applications and Users

Who uses ISO 15733:2015:

• Materials and mechanical testing laboratories performing ceramic composites tensile testing.
• R&D teams in aerospace, power generation, automotive and advanced manufacturing developing CMC components.
• Quality assurance and certification bodies verifying CMC mechanical performance for room‑temperature service. Practical uses:
• Comparing reinforcement architectures (1D/2D/3D) and processing routes.
• Verifying material batches and coatings (effective cross‑section considerations).
• Supplying standardized tensile data for design, simulation and component validation.

Related Standards

• ISO 7500‑1 - Verification of tension/compression testing machines (force measurement).
• ISO 3611 - Micrometers for external measurements.
• ISO 9513 - Extensometer calibration classes.
• ISO 17161 - Alignment procedures for tensile testing (referenced for alignment verification).

This standard ensures consistent, repeatable measurement of tensile properties for advanced ceramic composites, enabling reliable materials selection and qualification in high‑performance applications.