Mechanical characterisation of ITER-specification tungsten using tensile and small punch testing methods

Brahim Dif; Francisco Miranda; Juhani Rantala; Janne Heikinheimo; Aleksandr Zinovev; Dmitry Terentyev; Chih-Cheng Chang

doi:10.1016/j.fusengdes.2026.115688

Mechanical characterisation of ITER-specification tungsten using tensile and small punch testing methods

Brahim Dif^*
, Francisco Miranda
, Juhani Rantala
, Janne Heikinheimo
, Aleksandr Zinovev
, Dmitry Terentyev
, Chih-Cheng Chang

^*Corresponding author for this work

Catholic University of Louvain
Belgian Nuclear Research Centre (SCK CEN)
Ghent University

Research output: Contribution to journal › Article › Scientific › peer-review

Abstract

Tungsten is widely recognised for its exceptional properties. The material exhibits a high melting point, excellent thermal conductivity, and strong resistance to radiation damage, making it a key material for fusion energy applications.
In this work, two types of mechanical tests were conducted on ITER-specification tungsten (A.L.M.T, Japan): tensile and small punch testing (SPT). Tensile testing provides fundamental properties such as yield strength, and ultimate tensile strength in specific rolling directions. SPT on the other hand, which is biaxial in nature, offers comparable data using miniature specimens, thus enabling efficient characterisation with limited material. The study aims to characterise the mechanical properties of the material and explore a correlation factor between the two approaches.
Re-evaluation of the SPT correlation factors of ITER-specification tungsten in this study revealed noticeable deviation from the commonly adopted value in the European standard, with the yield strength factor showing the largest discrepancy. Furthermore, all correlation factors exhibited a noticeable temperature and directional (anisotropy) dependence, highlighting the importance of using material-specific values for accurate properties estimation.

Original language	English
Article number	115688
Journal	Fusion Engineering and Design
Volume	227
DOIs	https://doi.org/10.1016/j.fusengdes.2026.115688
Publication status	Published - Jun 2026
MoE publication type	A1 Journal article-refereed

Funding

This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No 101052200 — EUROfusion). The authors also acknowledge the support of Business Finland through the ECO-Fusion project.

Keywords

Coefficient factor
ITER-grade tungsten
Small Punch Test
Tensile testing
Ultimate tensile strength
Yield strength

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10.1016/j.fusengdes.2026.115688Licence: CC BY

j.fusengdes.2026.115688Final published version, 2.69 MBLicence: CC BY

Cite this

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title = "Mechanical characterisation of ITER-specification tungsten using tensile and small punch testing methods",

abstract = "Tungsten is widely recognised for its exceptional properties. The material exhibits a high melting point, excellent thermal conductivity, and strong resistance to radiation damage, making it a key material for fusion energy applications. In this work, two types of mechanical tests were conducted on ITER-specification tungsten (A.L.M.T, Japan): tensile and small punch testing (SPT). Tensile testing provides fundamental properties such as yield strength, and ultimate tensile strength in specific rolling directions. SPT on the other hand, which is biaxial in nature, offers comparable data using miniature specimens, thus enabling efficient characterisation with limited material. The study aims to characterise the mechanical properties of the material and explore a correlation factor between the two approaches. Re-evaluation of the SPT correlation factors of ITER-specification tungsten in this study revealed noticeable deviation from the commonly adopted value in the European standard, with the yield strength factor showing the largest discrepancy. Furthermore, all correlation factors exhibited a noticeable temperature and directional (anisotropy) dependence, highlighting the importance of using material-specific values for accurate properties estimation.",

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author = "Brahim Dif and Francisco Miranda and Juhani Rantala and Janne Heikinheimo and Aleksandr Zinovev and Dmitry Terentyev and Chih-Cheng Chang",

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AU - Dif, Brahim

AU - Miranda, Francisco

AU - Rantala, Juhani

AU - Heikinheimo, Janne

AU - Zinovev, Aleksandr

AU - Terentyev, Dmitry

AU - Chang, Chih-Cheng

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N2 - Tungsten is widely recognised for its exceptional properties. The material exhibits a high melting point, excellent thermal conductivity, and strong resistance to radiation damage, making it a key material for fusion energy applications. In this work, two types of mechanical tests were conducted on ITER-specification tungsten (A.L.M.T, Japan): tensile and small punch testing (SPT). Tensile testing provides fundamental properties such as yield strength, and ultimate tensile strength in specific rolling directions. SPT on the other hand, which is biaxial in nature, offers comparable data using miniature specimens, thus enabling efficient characterisation with limited material. The study aims to characterise the mechanical properties of the material and explore a correlation factor between the two approaches. Re-evaluation of the SPT correlation factors of ITER-specification tungsten in this study revealed noticeable deviation from the commonly adopted value in the European standard, with the yield strength factor showing the largest discrepancy. Furthermore, all correlation factors exhibited a noticeable temperature and directional (anisotropy) dependence, highlighting the importance of using material-specific values for accurate properties estimation.

AB - Tungsten is widely recognised for its exceptional properties. The material exhibits a high melting point, excellent thermal conductivity, and strong resistance to radiation damage, making it a key material for fusion energy applications. In this work, two types of mechanical tests were conducted on ITER-specification tungsten (A.L.M.T, Japan): tensile and small punch testing (SPT). Tensile testing provides fundamental properties such as yield strength, and ultimate tensile strength in specific rolling directions. SPT on the other hand, which is biaxial in nature, offers comparable data using miniature specimens, thus enabling efficient characterisation with limited material. The study aims to characterise the mechanical properties of the material and explore a correlation factor between the two approaches. Re-evaluation of the SPT correlation factors of ITER-specification tungsten in this study revealed noticeable deviation from the commonly adopted value in the European standard, with the yield strength factor showing the largest discrepancy. Furthermore, all correlation factors exhibited a noticeable temperature and directional (anisotropy) dependence, highlighting the importance of using material-specific values for accurate properties estimation.

KW - Coefficient factor

KW - ITER-grade tungsten

KW - Small Punch Test

KW - Tensile testing

KW - Ultimate tensile strength

KW - Yield strength

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Mechanical characterisation of ITER-specification tungsten using tensile and small punch testing methods

Abstract

Funding

Keywords

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ECO-Fusion: Finnish Ecosystem for Industrial Fusion Technology

Cite this

Mechanical characterisation of ITER-specification tungsten using tensile and small punch testing methods

Abstract

Funding

Keywords

Access to Document

Other files and links

Fingerprint

Projects

ECO-Fusion: Finnish Ecosystem for Industrial Fusion Technology

Cite this