Microstructures, Mechanical Properties and Deuterium Blistering Behavior of Chemically Prepared W–TiC Alloys

Abstract

The sintered W–(0, 0.1, 0.3 and 0.5) wt% TiC alloys and rolled W–0.1 wt% TiC alloys with different rolling reduction rates (65 and 83%) were fabricated using a wet-chemical method. The samples were irradiated with 367 shots of deuterium plasma in the Material and Plasma Evaluation System of the EAST tokamak for a total plasma exposure time of ~2000 s to evaluate their surface blistering behaviors. The microstructure, mechanical properties and surface blistering behavior of the samples after exposure were investigated. It was found that the average grain size of the sintered W–(0–0.5)TiC alloys decreased, and their relative density, microhardness and bending strength increased with the increase in the TiC content. The sintered W–0.5TiC alloy exhibited the smallest average grain size of 0.8 μm and the highest bending strength of 1163.6 MPa. Post-irradiation examinations showed that all of the sintered samples suffered surface blistering, but as the TiC content of the alloy was increased, the size of the blisters decreased. The sintered pure tungsten (PW) exhibited serious, ruptured blisters with sizes of ~1 to 25 μm; while the sintered W–0.5TiC alloy exhibited the best resistance to the deuterium plasma as evidenced by the small size of the blisters of <1–2 μm. In the case of the rolled samples, stream-like blisters and spot-like blisters were observed on the surfaces of the W–0.1 wt% TiC alloys with rolling reduction rates of 65 and 83%, respectively. The W–0.1 wt% TiC alloy with a higher rolling reduction rate exhibited a lower density of blisters and a lower degree of damage, which demonstrated that higher rolling reduction rate improved the deuterium plasma resistance of the rolled W–TiC alloys.