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-Ti(3)SiC(2)-TiC(x) multilayer materials based on combined transmission electron microscopy (TEM) analysis and first-principles calculations. We found that the undesirable phase transformation of Ti(3)SiC(2) is substantially enhanced near the SiC/Ti(3)SiC(2) interface, and it is suppressed near the Ti(3)SiC(2)/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 Ti(3)SiC(2) under irradiation can be improved by adding TiC(x), and it demonstrates that, in ceramics, interfaces are not necessarily beneficial to radiation resistance.