INHOMOGENEOUS DEFORMATION OF GRAINS AND ROUGHENING OF FREE SURFACE OF POLYCRYSTALLINE IRON DURING COMPRESSIVE PLASTIC DEFORMATION

S Inhomogeneous deformation at the free surface of an iron specimen during compressive plastic deformation is studied. The inhomogeneous deformation of grains in the plane of specimen surface is observed under scanning electron microscope, while the inhomogeneous deformation perpendicular to the surface is studied by measuring the surface roughness. It follows that the standard deviation of the measured strain for various grains as well as that of the measured surface roughness increase with the applied strain.