Applied Surface Science, Vol.258, No.20, 8061-8064, 2012
Surface nanostructure of a directionally solidified Ni-based superalloy DZ4 induced by high intensity pulsed ion beam irradiation
A high intensity pulsed ion beam (HIPIB) was used to irradiate directionally solidified nickel-based superalloy DZ4 with the following parameters: ion content consisting of Cn+ (30 at.%) and H+(70 at.%), an accelerating voltage of 250 kV, a pulse duration of 70 ns, a beam current density of 100 A/cm(2), irradiation times of 15. As revealed by SEM and TEM, the thermal effect was confined in a similar to 1.3 mu m thick surface zone, in which rapid melting and cooling occurred. A two-phase nanostructured layer of similar to 10 nm thick was formed on the outmost surface. The component phases are the gamma phase and the carbide with a particle size of similar to 5-10 nm. The presence of dense dislocation networks was observed in depth in the substrate metal, for instance similar to 20 mu m away from the sample surface, which is caused by shock wave impact. (c) 2012 Elsevier B.V. All rights reserved.