Dresden 2003 – scientific programme

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M: Metallphysik

M 12: Grenzfl
ächen II

M 12.2: Talk

Monday, March 24, 2003, 12:00–12:15, IFW D

High Temperature cyclic motion of tilt grain boundaries — •Badirujjaman Syed and Myrjam Winning — Institut fuer Metallkunde und Metallphysik, RWTH -Aachen, Kopernikusstr. 14, 52056 Aachen

The cyclic strain behaviour of grain boundaries has already been discussed in many articles. In the current work, the special attention has been focussed on the contributing factors for the driving force of cyclic grain boundary motion at high temperature cyclic deformation (both in elastic and plastic stress regime). The bicrystals were containing low and high angle tilt grain boundaries with wide varieties of misorientation angle and <112>-rotation axis. All bicrystals were deformed in three stages at several combinations of stress, temperature and number of cycles with a constant frequency of loading. The grain boundary displacement and deformed structure of each grain were framed by using standard optical microscope and the grain orientations were measured by EBSD technique in every stages. The slip activity differences and misorientation profiles were calculated from the deformed structure of bicrystals to ensure that there was a distinct evidence of irregular motion and in particular, the difference in dislocation density on both sides of the grain boundaries were found to be responsible for the motion of boundaries. The density of visible slip bands and deformation bands were noticed to be depend on the deformation conditions, and at the same time, the orientation along the slip lines of the same grain were differed by 3 to 5 degree. The results will be discussed particularly with regard to the different structure of low and high angle grain boundaries.