A New Low-Temperature Dislocation-Relaxation Peak in Aluminum

Amplitude-independent internal friction measurement is made on a zone-refined aluminum single crystal between 2–240 K by a composite oscillator method. In the lightly deformed state \(({}10⁻⁴)\), a new relaxation peak is clearly found at 11 K. The activation energy of this peak is derived to be about 0.01 eV by assuming the attack frequency f 0 =10 10 s -1 , and if the peak is due to the kink pair formation of the dislocation on the Peierls potential valley, the Peierls stress is estimated to be about 10 -5 µ (µ: shear modulus), which does not conflict with the yield stress of low-temperature plastic deformation measurements.