Impact of High-Power Heat Load and W Surface Carbidization on Its Structural-Phase Composition and Properties

This paper presents the results of a study on impact of high-power heat load and tungsten (W) surface carbidization on its structural-phase composition and physical-mechanical properties. In this regard, carbidization of a W surface was carried out by means of beam-plasma discharge in a simulation machine with plasma-beam installation. Certain data were obtained regarding temperature in control points of studied samples and temperature distribution throughout the monoblock element, made as a rectangle with an orifice for a cooling path, placed in a fusion reactor divertor. The paper demonstrates that changes in heat load power have an impact on microhardness, roughness, atomization of the carbidized W surface, and phase formation processes. It was established that a heat load q = 10 MW/m² has very little effect on the elemental composition of the surface and structural-phase composition of W samples with a carbidized layer. Growth of thermal load up to q = 20 MW/m² leads to a noticeable transformation of tungsten monocarbide (WC) into tungsten semicarbide (W₂C) and cracking of the W sample surface.