Ultrasonic Spectroscopy and X-Ray Diffraction Study for ARB Aluminum
It has been reported that accumulative-roll-bonded (ARB) aluminum having ultrafine grains shows an intriguing mechanical character that it is hardened by annealing and contrarily softened by deformation. In order to understand the mechanism of such a peculiar phenomenon, we have investigated the dislocation damping with ultrasonic spectroscopy and total amount of dislocations with the X-ray diffraction measurement. From the present measurements, we have found that the dislocations introduced by the ARB process are tangled but can be released with a large stress. Such dislocations accumulated in ultrafine grains play a significant role in the plastic deformation.
Young Won Chang, Nack J. Kim and Chong Soo Lee
K. Hirai et al., "Ultrasonic Spectroscopy and X-Ray Diffraction Study for ARB Aluminum", Materials Science Forum, Vols. 561-565, pp. 937-940, 2007