The overall economic damage caused by plagiarism is estimated at around 250 billion euro per year worldwide [1]. In addition to the economic damage to companies, forgers endanger the consumer by even bringing drugs and airplane parts of inferior quality to the market [1,2]. Consumers and products can be protected by forgery-proof safety markings. Conventional safety markings such as coding or seals can be easily forged. Forgery-proof safety markings are cost-intensive or use rare earths [2,3].
2-beam interference structuring is a method of applying safety markings with a periodic structure to different materials in one process step. Depending on the angle of view and the periodicity of the structures, the respective structure shimmers in a certain color. Thus, 2-beam interference structuring offers the possibility to create individual safety markings on different materials. The markings differ macroscopically due to the color reflection and microscopically due to the structure periodicity. Ultrafast laser radiation enables 2-beam interference structuring with periodic structure sizes around 1 µm. In this study, the heat influenced areas during 2-beam interference structuring are determined and the occurrence of a melt is characterized by scanning electron microscope analyses. For this purpose, steel and brass with different heat conductivity are structured and analyzed regarding melt formation and topography. Electron backscatter diffraction (EBSD) analyses characterize the influence of the structuring process on the microstructure in the marginal regions.