Effect of Ti content on preparation and properties of TiB2-SiC-Ti materials

Since the 21st century, the application of low atomic number material coating as the first wall of controllable thermonuclear fusion device has become one of the considerations of nuclear reactor builders in various countries. TiB2 material with high melting point, high hardness, low coefficient of thermal expansion, excellent wear resistance and low atomic number began to enter people's field of vision. Single TiB2 is difficult to be sintered and processed into other products. Therefore, adding ceramic and metal additives to TiB2 matrix material to effectively improve the mechanical properties and processability of the material has become the focus of corresponding researches. On the basis of the relevant literatures of TiB2-SiC, this paper considers adding metal Ti powder as the second additive to improve the properties of TiB2 composites. In this study, TiB2 and SiC were mixed at the mass ratio of 2 to 3, then two kinds of TiB2-SiC-Ti materials with different Ti contents were prepared by Spark Plasma sintering (SPS). The materials were irradiated by He+ at room temperature with energy of 60 keV and ion fluence of 2×1017ions/cm2. The material was heat treated at 1500℃ before and after irradiation. The performance of prepared samples, the effect of irradiation on materials and the results of high temperature heat treatment were characterized by Energy dispersive spectroscopy, Raman spectrum, Grazing angle x-ray diffraction spectrum, Vickers hardness, wear resistance test and Scanning electron microscope. The results show that the surface morphology and toughness of TiB2-SiC-Ti materials with 3% Ti mass friction are poor in SEM images. After the wear resistance test, the material surface is seriously worn and the wear resistance is poor. X-ray diffraction spectrum and Raman spectra show that the material is oxidized seriously at 1500℃, which is considered to be the cause of the poor compactness of materials. Raman spectra, Grazing angle X-ray diffraction spectrum and some Vickers hardness data before and after irradiation indicate that the material with low Ti content retains better crystal structure and have weaker irradiation hardening. In conclusion, the TiB2-SiC-Ti material with 3% Ti mass friction exhibits lower density, poor wear resistance and lower hardness, while the material with lower Ti mass fraction is more resistant to irradiation than the material with 6% Ti mass fraction at room temperature.