Texture Development and Mechanical Response in Microscale Reverse Extrusion of Copper

Axisymmetric reverse extrusion experiments were conducted on annealed Cu rod specimens to form cup-shaped structures with sidewall thicknesses ranging from similar to 400 mu m down to similar to 25 mu m. Scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) were used to examine the changes in Cu grain morphology and texture as a result of the forming operation. Pole figure (PF) and orientation distribution function (ODF) analysis of EBSD data showed the presence of the same texture components in the present small scale metal forming experiments as those observed previously in macroscale sheet metal rolling. Extrusion force - punch displacement curves were measured as a function of extruded cup sidewall thickness. The present work illustrates materials characteristics in small scale metal forming, and suggests directions of future work for bringing improved correspondence between experimentation and modeling for metal micro forming.