Tensile properties of baseline and advanced tungsten grades for fusion applications

This work aims to establish a mechanical reference database of tungsten materials that are currently under assessment of their susceptibility to neutron irradiation. To obtain the mechanical properties, we performed a set of parametric tests using mini-tensile sample geometry and fracture surface analysis. Six different types of tungsten-based materials were assessed: two commercial grades produced according to ITER specifications in Europe and China - i.e., Plansee (IGP) and AT&M (CEFTR), and four perspective lab-scale grades. These are grades reinforced with particles of TiC, Y2O3, and ZrC (W1TiC, W2YO, and W0.5ZC, respectively) as well as fine grain structure W (FG). Tests were performed in the temperature range 150-600 °C, selected specifically to reveal the ductile to brittle transition temperature and mechanisms of full plastic deformation. Most of the materials showed onset of the ductile behavior at 300 °C, except FG and IGP (in transverse orientation) grades. High yield strength and ultimate tensile strength were recorded for CEFTR, W0.5ZC, and W1TiC at the maximum investigated temperature (600 °C), which can be considered as promising for performance in the high-temperature regime. The lowest threshold temperature for ductility was determined to be 200 °C registered for the W0.5ZC grade, CEFTR (in longitudinal orientation) grades, and IGP (in longitudinal orientation) grades, hence demonstrating its high potential for divertor applications.