Radiation-induced thermal conductivity degradation in LiAlO2 and LiAl5O8 investigated by molecular dynamics
摘要
Radiation damage in lithium ceramic materials can severely degrade thermal transport properties, limiting their performance in nuclear environments such as tritium-producing burnable absorber rods (TPBARs). This study compares the intrinsic thermal conductivity degradation in single crystals of LiAlO2 and LiAl5O8 due to radiation-induced point defects. LiAlO2 shows a significant drop in thermal conductivity of up to 75% under increasing defect concentration and temperature, while LiAl5O8 retains over 50% of its thermal conductivity, even at high defect levels and elevated temperatures. The greater resilience of LiAl5O8 is attributed to its structural resilience, which suppresses defect generation and preserves phonon transport. Partial phonon density of states analysis reveals that Li and Al vacancies strongly suppress vibrational modes in LiAlO2, while LiAl5O8 shows minimal change, supporting its superior radiation tolerance. These results suggest LiAl5O8 to be a more durable candidate for high-temperature radiation environments.