Modelling and validation of laser based DED processes reinforced with nanoparticles in view of the effect of wetting

Abstract

Abstract Although the observation of wetting phenomena has a long history both in science and in everyday life, nanoscale wetting properties leave open a multitude of questions. Improving the properties of Direct Energy Deposition (DED) products through reinforcement with nanoparticles (NPs) is attractive. Due to the involved NPs, the wetting behaviour of the deposition differs from that in macroscales. Modelling and validation of a laser-based DED process reinforced with NPs in view of the effect of wetting is demonstrated in this study. Metal alloys reinforced with NPs (Ti6Al4V- and Al7075-TiC) are melted by laser light and deposit on a substrate. Heating of the alloys by laser light is tackled using a volumetric heat source model. A three-phase (solid, liquid and gas) melting and solidification simulation methodology is established in a continuum approach. Nanoparticles are treated in the Lagrangian framework. Effect of nanoparticle reinforcement on the wetting behaviour of melt bead during the printing process is investigated numerically, taking into account the influence of nanoparticles on contact angle and surface tension. Simulation results are compared with the experimental deposition of Ti6Al4V and Al7075 alloys through dimensional analysis of the tracks by macrography.