Strain Rate and Test Temperature Dependence on the Flow Properties of La2O3-Doped Tungsten

Tungsten and tungsten alloys are promising metals as protective materials for the armour in future fusion reactors. These metals exhibit the highest melting point, superior thermo-mechanical properties, low erosion and moderate neutron activation properties. The main drawback is their intrinsic brittleness at room temperature and their low recrystallization temperature. During thermal shock events in ITER, tungsten materials will exhibit various crack formations and failure mechanisms. The extensive heat loads on the surface of the material will create high thermal stresses, huge temperature rises and therefore large strain rates in the subsurface layers. This paper deals with the flow properties combining both temperature and strain rate effects of a lanthanum oxide dispersion strengthened tungsten material and the influence of grain orientation on its ductility. Promising results were obtained using a yield strength model based on a thermally-activated slip process that rationalizes the data.