About mechanism of the influence of relaxation on ultrasonic parameters

The experimental investigations of Rayleigh wave parameters have been performed on commercial pure aluminium at cyclic loading, low-carbon steel at the relaxation after unloading and Al-Cu alloy during active tension. It has been shown the possibility of using of Rayleigh wave parameter measurement for the estimation of dislocation structure change within the framework of the Granato–Lucke theory. It has been found that after unloading of low-carbon steel specimen the ultrasonic velocity changes in it during certain period. Such changing links with the decrease in the average length of dislocation segment because of the diffusion of impurity atoms to temporary arrested dislocations. The variation of ultrasonic velocity in being deformed Al-Cu alloy was analysed as a relaxation process accompanied by the dynamic strain aging. The possibility of such interpretation is proved by the estimate of the change in the average length of dislocation segment within the framework of the Granato–Lucke theory.The experimental investigations of Rayleigh wave parameters have been performed on commercial pure aluminium at cyclic loading, low-carbon steel at the relaxation after unloading and Al-Cu alloy during active tension. It has been shown the possibility of using of Rayleigh wave parameter measurement for the estimation of dislocation structure change within the framework of the Granato–Lucke theory. It has been found that after unloading of low-carbon steel specimen the ultrasonic velocity changes in it during certain period. Such changing links with the decrease in the average length of dislocation segment because of the diffusion of impurity atoms to temporary arrested dislocations. The variation of ultrasonic velocity in being deformed Al-Cu alloy was analysed as a relaxation process accompanied by the dynamic strain aging. The possibility of such interpretation is proved by the estimate of the change in the average length of dislocation segment within the framework of the Granato–Lucke theory.