Dresden 2003 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

M: Metallphysik

M 22: Mechanische Eigenschaften III

M 22.3: Talk

Tuesday, March 25, 2003, 15:15–15:30, IFW B

Plasticity at multiple length scales near Nb/Al₂O₃ interfaces — •Yonghe Liu, Dieter Brunner, Christina Scheu, and Manfred Rühle — Max-Planck-Institut für Metallforschung, Heisenbergstr.3, 70569 Stuttgart

The plasticity of a single crysatlline Nb layer sandwich-bonded by diffusion bonding between sapphire pieces was investigated at macro, meso, and micro length scales. Compression tests were performed and, during plastic straining, two surfaces of the Nb layer were observed with an optical full field method (OFM) to measure local strains. Besides, TEM observations of the same specimen were performed before and after deformation. The compression samples were characterized by two interfaces of the sandwich joint with orientations of (0001)[-1100]//(1-10)[110] and (0001)[-2110]//(1-10)[110], respectively. The measurements enabled to correlate the macroscopic mechnical behavior represented by stress strain curves with the OFM strain maps with a resolution down to mesoscales. The strain localization observed by means of OFM strain maps was compared with the motion of dislocations at micro length scale received from the TEM observations. It was found that dislocations mainly move along two directions: along the maximum shear direction, and parallel to the interfaces. The movement of the dislocation will finally lead to the strain localization in the Nb layers. (in English)