ISO 24046:2022

Overview

ISO 24046:2022 specifies a standardized tensile test method for resin-impregnated yarns made from ceramic fibres (fine/advanced ceramics) used as reinforcements in composite materials. The standard defines how to determine tensile strength, tensile modulus of elasticity, and strain at maximum force of an epoxy‑impregnated yarn specimen at ambient temperature. Results are intended for quality control and relative comparison of reinforcing fibres in fibre‑reinforced ceramic matrix composites (CMCs), and are explicitly distinct from dry‑tow filament tests described in ISO 22459.

Key topics and requirements

• Scope and applicability: Test applies to yarns of ceramic fibres used as reinforcements in composites; ambient temperature testing.
• Specimen preparation: Uniform impregnation with a compatible resin (typically thermosetting epoxy); resin selection guidance-cured resin failure strain should be at least twice, preferably >3×, the specimen’s failure strain.
• Apparatus: Impregnation bath and rollers, curing oven, tensile-testing machine, extensometer (or displacement-based measurements with compliance correction), balance, ruler.
• Test procedure:
  • Impregnate and cure yarn specimens to produce smooth, uniformly impregnated samples.
  • Condition specimens in specified atmospheres prior to testing.
  • Apply tensile force at controlled displacement rate until failure; measure longitudinal deformation via extensometer or via corrected grip displacement.
  • Correct for load train compliance (grips, fixtures, tabbing) when extensometer is not used.
• Calculations and reporting:
  • Compute tensile strength (maximum force / initial dry yarn cross-sectional area), tensile modulus (slope of force–deformation curve divided by dry yarn area), and strain at maximum force.
  • Follow prescribed methods for compliance calculation, instantaneous total compliance, and statistical treatment.
• Informative annexes: Examples of heat‑curable epoxy systems, impregnation apparatus, and extensometer designs.

Applications and users

• Primary users: Fibre manufacturers, composite material producers, independent testing laboratories, and R&D groups working on CMCs.
• Practical uses:
  • Quality control of ceramic reinforcing yarns.
  • Comparative evaluation of fibre batches or supplier materials.
  • Supporting material selection and qualification for high‑temperature/aerospace components (e.g., jet engine and gas turbine parts).
  • Data input for composite design and reliability assessments.

Related standards

• ISO 22459 - tensile tests on dry tows (distinct from ISO 24046 outputs)
• ISO 1889 - determination of linear density of reinforcement yarns
• ISO 7500-1 - calibration/verification of tensile testing machines
• ISO 10119 / ISO 10548 - related carbon fibre property methods

Keywords: ISO 24046:2022, resin-impregnated yarns, tensile properties, ceramic fibres, fine ceramics, tensile strength, tensile modulus, CMCs, test method, quality control.