Effect of Deformation Nanostructuring on the Ion-Beam Erosion of Copper

The effect of deformation nanostructuring on the ion-beam erosion of copper at a high fluence of irradiation with 30 keV argon ions is experimentally studied. To form an ultrafine-grained structure with a grain size of ~0.4 μm in copper samples with an initial grain size of about 2 μm, deformation nanostructuring by high-pressure torsion is used. It is found that when a layer with a thickness comparable to the grain size is sputtered, a steady-state cone-shaped relief is formed on the copper surface, the appearance of which does not change with increasing irradiation fluence. It is shown that the smaller the grain size in copper, the greater the concentration and the smaller the height of the cones on the surface. The cone inclination angles, close to 82°, as well as the sputtering yield of 9.6 at/ion, are practically independent of the grain size of copper, the thickness of the sputtered layer, and the irradiation fluence. Calculations using the SRIM program show that, when taking into account the redeposition of atoms from the walls of the cones, the sputtering yield of a cone-shaped copper relief Y_c is 3.5 times less than the sputtering yield of a single cone, 1.2 times greater than the sputtering yield of a smooth surface, and the value of 9.25 at/ion is close to the experimentally measured one.