2017 Volume 58 Issue 11 Pages 1519-1523
In this study, a commercially AISI 5140 steel with two different levels of initial surface state (initial high-roughness (IHR) and initial low-roughness (ILR)) was surface-treated by large-area pulsed electron beam irradiation (LPEBI). Surface morphology in 2D and 3D of the two types of samples after LPEBI treatment was characterized. The results show that the surface roughness of IHR samples decreases clearly with increasing LPEBI pulse numbers, while an opposite trend is found in the ILR samples. It is considered that the final surface roughness is influenced by surface remelting and formation of crater-like structures (CLSs) in local regions. For the IHR samples with amounts of mechanical scratches, the remelting plays the leading role, owing to the high surface energy which provides extra driving force for remelting during LPEBI. In contrast, such extra driving force is less due to the relatively flat surface of the ILR samples, instead remelting the surface suffers from the formation of CLSs in localized region. Compared to the formation of localized CLSs, the surface remelting is beneficial to surface roughness of the LPEBI processed samples.