Inhomogeneous deformation of grains and roughening of free surface of polycrystalline copper during compressive plastic deformation.

Inhomogeneous deformation at the free surface of copper specimen during compressive plastic deformation is studied. The inhomogeneous deformation of grains in the plane of specimen surface is observed by scanning electron microscope, while the inhomogeneous deformation perpendicular to the surface is studied by measuring surface roughness. It was found that the variations of the measured values of strain in each grain as well as the surface roughness in crease with the applied strain. Discussion is made on the relation between the variations of strain in each grain and the surface roughness.