抄録
Bordoni relaxation (BR) of internal friction peaks in fcc metals around liquid nitrogen temperatures, was investigated experimentally using a pure aluminum crystal by a resonant bar method of 51 kHz. Each time after slight deformations or subsequent anneals, we measured the BR at temperatures between 78 K and 250 K. Usually the Bordoni relaxation consists of two broad peaks, i.e., the Bordoni peak (B2 peak) at higher temperature (～180 K) and Niblett-Wilks peak or shoulder (B1 peak) at lower temperature (～120 K). It was not expected that after an anneal at 800 K in air, there appeared four sharp internal friction peaks for the temperature range of BR. The peak located at 120 K seems related with B1 peak. The remaining three peaks seem related with B2 peak. These sharp peaks are found probably for the first time.
