Analysis of high heat flux tested tungsten mono-blocks by hardness and microstructural profiling

Abstract

The integrity of tungsten plasma facing component mockups was investigated by microstructure and hardness measurement before and after high heat flux (HHF) test. The mockups consisting of five ITER-like tungsten mono-blocks were fabricated employing gas pressure casting and hot radial pressing (HRP) method. The tungsten blocks were machined from rolled W plates of two commercial suppliers. The tested mockups showed discernible results in response to different heat flux conditions of which increased heat flux was of importance. Post-mortem analysis of the tungsten armor of the HHF tested mockups were conducted through microstructure and hardness profiling from surface along the depth. The Vickers hardness profile measured from the surface into the depth showed notable decrease around 300 μm ∼ 1600 μm depth after HHF test compared to that before the test. The depth and magnitude of hardness change was dependent on the heat loading condition and the position in the tungsten block. The behavior of hardness indicating the materials property of tungsten showed correlation with the microstructural change measured by electron back scatter diffraction (EBSD).