ISO 14574:2025

Overview

ISO 14574:2025 - Fine ceramics (advanced/technical ceramics) - Mechanical properties of ceramic composites at high temperature - Determination of tensile properties - specifies standardized procedures for measuring the tensile behaviour of ceramic matrix composites (CMCs) with continuous fibre reinforcement at elevated temperatures. The standard applies to testing in air, vacuum, and inert gas atmospheres, and covers uni‑directional (1D), bi‑directional (2D) and multi‑directional (xD) constructions, including carbon‑fibre‑reinforced carbon (C/C) materials. It defines terminology (gauge length, calibrated length, controlled‑temperature zone, tensile stress/strength, etc.) and notes practical considerations such as anti‑oxidation coatings for high‑temperature exposure in air.

Key topics and technical requirements

• Scope and definitions: precise terms for test temperature, gauge length (L0), calibrated length and cross‑section areas (apparent vs effective).
• Apparatus and setup: requirements for the test machine, load train, test chamber, heating arrangements, strain gauges/extensometers, temperature sensors and data acquisition.
• Controlled‑temperature zone: the standard defines the zone around the gauge length where temperature must be within ±50 °C of the test temperature.
• Specimen design and preparation: recommended specimen types for 1D/2D/xD composites, machining, and the number of specimens.
• Test procedures: temperature calibration, setting extensometers, atmosphere control, displacement rates and measurement of dimensions.
• Calculations and outputs: methods to compute tensile strength, strain at maximum force, and tensile modulus (including handling linear and non‑linear behaviour).
• Validity, uncertainties and reporting: criteria for test validity, guidance on uncertainty estimates, and required test report contents.
• Informative annexes: Annex A illustrates tensile modulus; Annex B provides a temperature calibration method using a cartographic specimen with thermocouples.

Applications and who uses ISO 14574:2025

• Materials and mechanical testing laboratories performing high‑temperature tensile characterization of CMCs.
• R&D and design engineers in aerospace, power generation (gas turbines), automotive (exhaust/thermal components), defense and advanced manufacturing who need reliable mechanical property data.
• Manufacturers of advanced ceramics and CMC components seeking standardized qualification and quality control methods.
• Academic and industrial researchers validating models of high‑temperature behaviour, and certification bodies requiring reproducible test methods.

Practical benefits

• Provides repeatable, comparable tensile data for CMC selection and design.
• Ensures consistent handling of coatings, atmospheres and temperature control crucial to high‑temperature testing.
• Supports product qualification, material development and regulatory compliance.

Related standards

• ISO 20507 (vocabulary), ISO 19634 (composite symbols/notations), ISO 3611, ISO 7500‑1, ISO 9513 and IEC 60584‑1 (thermocouples) - referenced for measurement, calibration and instrumentation.