Influence of crystallographic texture and external electromagnetic fields on sub-ns pulsed UV laser derived nanostructures

Resumen del trabajo presentado al European Congress and Exhibition on Advanced Materials and Processes (EUROMAT), celebrado en Estocolmo (Suecia) del 1 al 5 de septiembre de 2019.[Introduction/Purpose]: Generation of Laser-induced Periodic Surface Structures (LIPSS) is a general phenomenon that has been observed in a broad range of materials and intensively studied since the commercial availability of ultra-short pulsed lasers. It has been observed that the morphology of LIPSS can be controlled by the selection of adequate laser processing parameters.[Methods]: In this work, we have analysed the generation of LIPSS in different metal surfaces using a sub-ns (300 ps) pulsed UV laser, with a laser-line scanning configuration. In addition to the laser parameters, different variables that can modify how LIPSS are generated, have been explored. EBSD studies have been used to determine the crystallographic direction of each grain at the surface of the material and how it modifies the characteristics of nanostructure generation. Experiments have also been performed under different electromagnetic fields during laser processing.[Results]: It has been observed that crystallographic orientation of grains has a significant influence on the generation of nanostructures. When prominent cones are generated, they appear only in some grains with a given orientation, for instance, (001) planes in stainless steel. In the case of ripples, period, size and orientation are also modified. For some configurations of external electromagnetic fields, the uniformity of the nanostructure can also be improved in extended areas.[Conclusions]: It is well established that nature and ordering of LIPSS nanostructures depend on the laser parameters, mainly irradiance and polarization, and on the material. In this work, it has been determined that for a given material, this order can be modified depending on the crystallographic orientation of each particular grain and using adequate external electromagnetic fields.The authors gratefully acknowledge the financial support from MINECO-AEI-FEDER (project ENE2017-83669-C4-1-R and MAT2016-79866-R), from PHOBIC2ICE (EU GA 690819) and SPRINT (EU H2020-FET-OPEN/0426) projects and from Gobierno de Aragón (research group T54_17R).Peer reviewe