Degradation of Silicon Carbide by Molten Lithium

The mechanical behavior of silicon carbide exposed to molten lithium was evaluated at exposure temperatures from 200° to 1000°C. For temperatures up to 600°C, there was little change in strength and the fracture was controlled by preexisting surface flaws on the specimen surface or edges. Above 600°C, two strength populations developed: a relatively high‐strength group characterized by transgranular fracture and a low‐strength group characterized by intergranular degradation. Quantitative chemical analysis was used to explain the lithiuminduced strength degradation. This information, coupled with the fractographic analysis, led to a description of the corrosion mechanism.