ISO 13067:2020

Overview

ISO 13067:2020 - "Microbeam analysis - Electron backscatter diffraction - Measurement of average grain size" defines procedures for measuring average grain size from two‑dimensional polished cross‑sections using electron backscatter diffraction (EBSD). The standard covers acquisition of EBSD orientation and pattern quality data, identification of grain boundaries, post‑acquisition processing, calculation of sectional grain sizes and derivation of average grain size (with stereological relation to 3D grain size), and guidance on reporting and measurement uncertainty.

Keywords: ISO 13067, EBSD, electron backscatter diffraction, grain size measurement, microbeam analysis, average grain size.

Key technical topics and requirements

• Scope and definitions: Clear terminology distinguishing sectional grain sizes (2D) from mean/3D grain size and definitions for step size, pixel, orientation, pattern quality, misorientation/disorientation, and grain boundary.
• Equipment and calibration: Hardware and software requirements for EBSD mapping, plus references to magnification and linear calibration guidelines.
• Map acquisition:
  • Specimen preparation and stage positioning
  • Choice of step size and map area to obtain statistically representative grain populations
  • Determination of required angular accuracy for indexing
  • Considerations for plastically deformed materials and complex duplex microstructures
• Data handling and processing:
  • Definition and handling of grain boundaries (including incomplete and special boundaries)
  • Post‑acquisition treatments and data-cleaning procedures (indexing reliability, pattern quality filters)
  • Measurement of sectional grain sizes from orientation maps and calculation of average grain size using standardized procedures
• Uncertainty and reproducibility:
  • Guidance on sources of error, expected precision (informed by round‑robin data), and minimum number of grains to measure
• Reporting: Required elements for clear reporting of methods, parameters, and uncertainty estimates
• Informative annexes: Practical examples on grain size measurement (Annex A) and reproducibility data (Annex B)

Practical applications - who uses ISO 13067

• Materials scientists and metallurgists measuring grain size effects on strength, toughness, hardness and other properties
• Quality and testing laboratories applying EBSD for production control of alloys, coatings, thin films and duplex materials
• Researchers studying texture, deformation, recrystallization and grain‑structure evolution
• Laboratories seeking traceable EBSD-based grain size measurements consistent with international standards

Related standards

• ISO 24173 - Guidelines for orientation measurement using EBSD (terminology and measurement practice)
• ISO 16700 - SEM image magnification calibration
• ISO 23833 - Microbeam analysis vocabulary (EPMA)
• ISO/IEC 17025 - Competence of testing and calibration laboratories

ISO 13067:2020 helps organizations implement robust, reproducible EBSD workflows for quantitative grain‑size analysis and ensures consistency when converting 2D sectional measurements to meaningful average grain‑size metrics.