Damage caused by He and D plasma exposure in Mo/Zr-added W-Y2O3 composites

In the present study, we developed Mo- and Zr-added W-Y2O3 composites, and investigated their surface damage, including commercially available W induced by He and D as well as He and D mixture plasmas. Blistering was not observed in the D-plasma-irradiated W and W composites. The thickness of the damaged surface layer due to He plasma exposure of the W-Mo-Y2O3 composite was similar to that of W. However, the thickness of the damaged surface layer of the W-Y2O3 composite was half that of W. In addition, the thickness of the damaged surface layer of the W-Zr-Y2O3 composite was further improved by 5 times. Y2O3 nanoparticles, especially refined Zr-Y-O nanoparticles, act as He trap sites to suppress the formation and growth of He bubbles. Furthermore, the W-O-Y and W-O-Zr-Y nanoparticles increased the solubility of He and delayed He diffusion, hindering the formation of He bubbles.