Influence of the irradiation temperature on the surface structure and physical/chemical properties of Ar ion-irradiated bulk metallic glasses

Abstract Surface treatments using multiple Ar ion irradiation processes with a maximum energy and fluence of 200 keV and 1 × 10 16  ions/cm 2 , respectively, have been performed on two different metallic glasses: Zr 55 Cu 28 Al 10 Ni 7 and Ti 40 Zr 10 Cu 38 Pd 12 . Analogous irradiation procedures have been carried out at room temperature (RT) and at T  = 620 K (≈0.9  T g , where T g denotes the glass transition). The structure, mechanical behavior, wettability and corrosion resistance of the irradiated alloys have been compared with the properties of the as-cast and annealed ( T  = 620 K) non-irradiated specimens. While ion irradiation at RT does not significantly alter the amorphous structure of the alloys, ion irradiation close to T g promotes decomposition/nanocrystallization. Consequently, the hardness ( H ) and reduced Young’s modulus ( E r ) decrease after irradiation at RT but they both increase after irradiation at 620 K. While annealing close to T g increases the hydrophobicity of the samples, irradiation induces virtually no changes in the contact angle when comparing with the as-cast state. Concerning the corrosion resistance, although not much effect is found after irradiation at RT, an improvement is observed after irradiation at 620 K, particularly for the Ti-based alloy. These results are of practical interest in order to engineer appropriate surface treatments based on ion irradiation, aimed at specific functional applications of bulk metallic glasses.