Surface layers and bulk material were studied in alloys with differing melting points which had been exposed to high-power ion beams. It was found that, regardless of ion-beam powers of 12 to 50MW/cm2, in the absence of surface melting, the characteristic feature of the surface was crater formation. Disclination and microtwin-type rotational defects, surface-layer amorphization and dislocation structures with various densities were observed inside and outside of the craters. A theory was proposed for the formation of high local stress gradients under bombardment, and their relaxation via disclination-type rotational effects. A high-energy sub-structure with a high continuum disclination density was found experimentally.

Structure-Phase States of the Metal Surface and Undersurface Layers after Treatment by Powerful Ion Beams. A.D.Korotaev, S.V.Ovchinnikov, J.I.Pochivalov, A.N.Tyumentsev, D.A.Shchipakin, M.V.Tretjak, I.F.Isakov, G.E.Remnev: Surface and Coatings Technology, 1998, 105[1-2], 84-90