Aluminium and titanium alloys surface behaviour under argon and helium ion exposure

Samples of aluminium alloy 2024 and titanium alloy Ti-6Al-4V are irradiated with 2 keV helium (He) and argon (Ar) ion fluxes using FALCON ion source. Cone-like structures are found to be formed on the surface of two Al (2024) samples due to both irradiation conditions: Ar and He ions exposure reaching total fluence 9.75 x 10(25) m(-2) and total charge 150 Coulomb per sample. Ar ions exposure of Ti-6Al-4V causes cones formation, while exposure for He ions causes only physical sputtering morphology at the same fluence. Chemical composition of grown structures is obtained from energy dispersive spectroscopy (EDS). Surface roughness and roughness profile are investigated with confocal microscope. Hardness of irradiated surfaces is obtained from results of Vickers hardness test. Residual stresses after irradiation and phase composition are measured by X-ray Diffraction spectroscopy (XRD). The mechanisms of cones growth on alloys surface are surface radiation-stimulated diffusion and ion induced collision cascades evolution.