Progress in the development of insulator coating for liquid lithium blankets

Recent Progress in Research of Solid Tritium Breeder Materials Li2TiO3: A Review

During the past decades, fusion reactor fuels such as deuterium and tritium have been extensively investigated due to increasing interest in nuclear fusion energy. Tritium, which is scarce in nature, needs to be fabricated by tritium breeder materials. Among the commonly investigated tritium breeder materials, lithium titanate (Li2TiO3) is recognized as one of the most promising solid tritium breeder materials because of its considerable lithium (Li) atomic density, low activation, excellent chemical stability, and low-temperature tritium release performance. This paper aims to provide a systematic review of the current progress in Li2TiO3 preparation methods as well as the high Li density, tritium release performance, irradiation behavior, and modification technologies of Li2TiO3 pebbles. Li2TiO3 can be synthesized by strategies such as solid-state, sol–gel, hydrothermal, solution combustion synthesis, and co-precipitation methods. Among them, the hydrothermal method is promising due to its simplicity and low cost. Many researchers have begun to focus on composite ceramic pebbles to further improve tritium breeder performance. This will provide a new direction for the future development of Li2TiO3 pebbles. The present review concludes with a summary of the preparation methods currently under development and offers an outlook of future opportunities, which will inspire more in-depth investigation and promote the practical application of Li2TiO3 in this field.

Interface Characteristics of Ti-Clad V–4Cr–4Ti Alloy Diffusion-Bonded Joint Produced by Hot Forging

Diffusion bonding of V–4Cr–4Ti alloy to pure titanium (Ti) was carried out by hot forging in the temperature range between 1150 °C and 950 °C. The microstructure and mechanical properties of the bonded joint were determined by using light optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), micro-hardness measurements, and shear tests. The results indicate that the sound dissimilar joint can be obtained through hot forging processes. The interface has a width of about 100 μm and can be divided into two distinctive zones: a Widmanstatten structure zone and a β-Ti phase structure zone. According to the micro-hardness distribution profile across the substrates and the interface, the largest hardness of 332 HV was measured in a narrow region between the Ti substrate and the joint, which is remarkably higher than that of the substrates (Ti of 190 HV and V–4Cr–4Ti alloy of 258 HV). The lowest hardness of only 182 HV was found in a region in the V–4Cr–4Ti substrate adjacent to the joint. The shear test showed that the joint has a bonding strength higher than 165 MPa and a fracture of the joint took place in the region with the highest hardness.