Enhancing the phase stability of ceramics under radiation via multilayer engineering

In metallic systems, increasing the density of interfaces has been shown to be a promising strategy for annealing defects introduced during irradiation. The role of interfaces during irradiation of ceramics is more unclear because of the complex defect energy landscape that exists in these materials. Here, we report the effects of interfaces on radiation-induced phase transformation and chemical composition changes in SiC-Ti₃SiC₂-TiC_x multilayer materials based on combined transmission electron microscopy (TEM) analysis and first-principles calculations. We found that the undesirable phase transformation of Ti₃SiC₂ is substantially enhanced near the SiC/Ti₃SiC₂ interface, and it is suppressed near the Ti₃SiC₂/TiC interface. The results have been explained by ab initio calculations of trends in defect segregation to the above interfaces. Our finding suggests that the phase stability of Ti₃SiC₂ under irradiation can be improved by adding TiC_x, and it demonstrates that, in ceramics, interfaces are not necessarily beneficial to radiation resistance.