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M: Metallphysik

M 13: Grenzfl
ächen

M 13.4: Fachvortrag

Dienstag, 12. März 2002, 17:15–17:30, H4

Microsturctural Changes during High Temperature Low Cycle Deformation — •Syed Badirujjaman and Myrjam Winning — Institut für Metallkunde und Metallphysik, RWTH Aachen

The mobility of grain boundaries under certain conditions is a key factor for the evolution of polycrystalline microsructures and material properties. The current study was performed to investigate the details of grain boundary motion, microsturctural changes and microtexture evolution during high temperature low cycle deformation (HT-LCF) of high purity aluminium bicrystals. Bicrystals include low angle, high angle as well as random type grain boundaries. The bicrystals were deformed under stress controled low cycle fatigue condition by using several combinations of parameters (i.e different amplitude of stress, temperatures and no of cycle) during each deformation step at constant rate of loading. The displacement of grain boundaries was measured by using optical microscope (LEICA), and the microstructural features, microtexture evolution and orientation of individual grain were recorded by the Electron Backscatter Diffraction technique (EBSD) using a standard Scanning Electron Microscope (JEOL 6100) after each deformation step without additional surface preparation. The deformation structure occured in each grain during cyclic deformation. The grain boundary steps during motion, and the change of misorientation angle were found remarkable during cyclic deformation. In several cases the slip bands and deformation bands were noticed. It is also seen that the nature and rate of grain boundary motion were not similar for the different deformation conditions.