Overview
ISO 28401:2024 - "Light metals and their alloys - Titanium and titanium alloys - Vocabulary" is the second edition vocabulary standard that defines terms and definitions related to titanium and titanium alloys. Published by ISO/TC 79/SC 11, this document replaces ISO 28401:2010 and consolidates consistent, internationally agreed terminology for titanium sponge, alloys, phases, microstructures, product forms and processing methods. The standard supports clear technical communication and accurate specifications across manufacturing, procurement and testing.
Key topics
The standard provides authoritative definitions across organized sections, including:
- Material terminology
- titanium sponge, alloy, alloying element, impurity, master alloy, heat‑treatable and non‑heat‑treatable alloys.
- Phase classification
- α (alpha) phase, β (beta) phase, α/β mixtures, β‑transus temperature, and phase stabilisers.
- Microstructure morphology
- equiaxed α, acicular (Widmanstätten) α, grain‑boundary α, elongated α, bimodal structures.
- Product forms
- unwrought products (ingots, electrodes, additive manufacturing products), wrought products (billets, rods/bars, wire, tubes, profiles), castings and intermediate forms (drawing stock, wire rod).
- Processing and melting methods
- terminology covering vacuum arc remelting (VAR), electron beam melting (EBM), plasma arc melting (PAM) and remelting electrodes.
- Surface condition, applications, types and grades
- standardized terms for surface state, material types, titanium grades and compounds.
- Normative content
- Annex A (normative) establishes the dividing line between unalloyed titanium and titanium alloys; the document contains a bibliography and index for further reference.
Note: ISO 28401:2024 contains no normative references and is intended as a vocabulary resource rather than a performance specification.
Applications and users
ISO 28401:2024 is essential for stakeholders who require precise and consistent language about titanium and titanium alloys:
- Materials engineers and metallurgists defining microstructure, phases or heat treatment.
- Product designers and specification writers preparing contracts, drawings and technical data sheets.
- Procurement, quality assurance and inspection teams verifying material conformity and certificates.
- Manufacturers and additive‑manufacturing service providers documenting processes (VAR, EBM, PAM).
- Standards developers, regulators and testing laboratories harmonizing terminology for international trade.
By using this vocabulary, organizations reduce ambiguity in specifications, improve interoperability of technical documents, and support clearer supply‑chain communication for titanium products.
Related standards
- Prepared by ISO Technical Committee ISO/TC 79, Subcommittee SC 11 (Titanium).
- Part of the ISO 28401 series - see the ISO website for the full list and related light‑metals standards.
