· 94 · IMP & HIRFL Annual Report 2018 Fig. 3 (color online) (a) and (b) S parameter of samples irradiated at 1×10 16 ions/cm 2 500 ℃ and 1×10 17 ions/cm 2 500 ℃ as a function of depth. (c) and (d) S-W plots for samples irradiated at 1×10 16 ions/cm 2 500 ℃ and 1×10 17 ions/cm 2 500 ℃. References [1] Z. M. Sun, Int. Mater. Rev. 56(2011)143. [2] D. W. Clark, S. J. Zinkle, M. K. Patel, C. M. Parish, Acta Materialia., 105(2016)130. [3] Q. Huang, R. D. Liu, L. Yan, J. Nucl. Mater., 465(2015)640. [4] Z. J. Zhu, M. Y. Yao, J. J. Shi, J. Nucl. Mater., 508(2018)12. [5] F. Wang, Q. Su, M. Nastasi, Ceramics International, 44(2018)14686. 5-9 Investigation on Microstructure and Surface Morphology of Tungsten Carbide Irradiated with He Ions Tai Pengfei, Sun Jianrong and Wang Zhiguang According to the present design of ITER, the divertor armor is consisted predominantly of carbon fiber com- posites and tungsten (W) with carbon coatings in the areas subject to the highest heat load [1] . Due to sputtering and subsequent re-deposition, mixing of these materials will occur. Studying radiation damage in tungsten carbide (WC) is of importance both due to its applications of plasma facing materials and due to the presence of WC in the divertor of fusion reactors [2] . In this work, WC samples with the purity of 99.9 % and 10 mm×10 mm×1.0 mm in size were implanted by 500 keV He + ions from 320 kV Multi-discipline Research Platform for Highly Charged Ions (IMP, Lanzhou). The irradiation doses were from 1×10 15 to 1×10 18 ions/cm 2 at room temperature, and from 1×10 15 to 1×10 17 ions/cm 2 at 800 ℃. After the irradiation, the lattice structure and surface morphology of the samples have been investigated by grazing incident XRD and AFM. As is shown in Fig. 1, the XRD results indicated that at room temperature, the characteristic peak intensity of two phases (W 1 C 1 and W 2 C 1 ) were decreasing meanwhile the FWHMs were broadened with the increasing of implanted He + dose, which means the increasing of lattice damage. At the implantation temperature of 800 ℃,