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

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. • Small punch testing (SPT) and tensile testing are applied to evaluate the mechanical behaviour of ITER-grade tungsten. • The yield strength and ultimate tensile strength can be extracted from SPT. • The SPT correlation factors were re-evaluated, the yield strength factor deviates noticeably from the EN standard. • The SPT correlation factors exhibit temperature dependence. • Using calculated factors in this study can improve the accuracy in estimation of mechanical properties of ITER tungsten.