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Laser Operating Windows Prediction in Selective Laser-Melting Processing of Metallic Powders: Development and Validation of a Computational Fluid Dynamics-Based Model
摘要： The rapidly ascending trend of additive manufacturing techniques requires a tailoring of existing solidification models and the development of new numerical tools. User-friendly numerical models can be a valid aid in order to optimize operating parameter ranges with the scope to extend the modelling tools to already existing or innovative alloys. In this paper a modelling approach is described simulating the generation of single tracks on a powder bed system in a selective laser melting process. The approach we report attains track geometry as a function of: alloy thermo-physical properties, laser speed and power, powder bed thickness. Aim of the research is to generate a numerical tool able to predict laser power and speed ranges in manufacturing porosity-free printed parts without lack of fusion and keyhole pores. The approach is based on a simplified description of the physical aspects. Main simplifications concern: the laser energy input, the formation of the pool cavity, and the powder bed thermo-physical properties. The model has been adjusted based on literature data providing the track’s geometry (width and depth) and relative density. Such data refer to different alloys. In particular, Ti6Al4V, Inconel625, Al7050, 316L and pure copper are considered. We show that the printing process presents features common to all alloys. This allows the model to predict the printing behavior of an alloy from its physical properties, avoiding the need to perform specific experimental activities.
关键词： metallic alloys,numerical model,selective laser melting,additive manufacturing,laser operating window
更新于2025-09-23 15:21:01
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Particle distribution in transient plasmas generated by ns-laser ablation on ternary metallic alloys
摘要： Understanding the fundamental mechanisms behind industrial laser-based technologies represents one the cornerstones of the development and tailoring of new materials. With the thin-film deposition using laser ablation being one of the most important techniques for obtaining complex materials with controllable stoichiometry, there is a high request for both experimental and theoretical studies towards understanding the behavior of multi-component alloys under high-power laser irradiation. Here we investigate the laser ablation process on two ternary metallic alloys (Cu–Mn–Al and Fe–Mn–Si) by means of space-and time-resolved optical emission spectroscopy and fast camera imaging with the focus being on the spatial distribution of each composing element. Information regarding the kinetic and thermal energy of the ejected particles is extracted and discussed in the framework of an inner structuring of the laser-produced plasmas based on a mass and energy distribution. The hypothesis is then verified by implementing a fractal analysis to the multi-component plasmas. The theoretical fractal approach offers results in good agreement with the experimental data gives important insight in the inner dynamics of complex laser-produced plasmas.
关键词： Ternary metallic alloys,Optical emission spectroscopy,Fractal analysis,Fast camera imaging,Laser ablation
更新于2025-09-12 10:27:22