Thermal shock response of fine- and ultra-fine-grained tungsten-based materials

Abstract

In this work, the focus is on the thermal shock analysis of fine- and ultra-fine-grained tungsten-based materials doped with 0.5–1.1 wt% TiC that showed in previous studies improved ductility at low temperatures and also performed well when exposed to neutrons and ions (H/He). Herein, the resistance of the material to crack formation is evaluated by applying edge-localized mode-like loads (n=100) with an energy density of 1 MJ m-2 at various temperatures up to 150 °C by means of an electron beam facility. The results indicate that the cracking threshold is significantly reduced even down to room temperature when the oxygen content is reduced and the combination of grain size, TiC particle size and distribution of TiC-particles to almost each grain boundary reaches its optimum. This is achieved by a post-manufacturing treatment of the material at 1650 °C using the material's superplasticity caused by grain boundary sliding at this temperature, which changes the material's microstructure from ultra-fine grains surrounded by weak grain boundaries to fine grains with significantly strengthened grain boundaries.