Towards additive manufacturing of compressor impellers: 3D modeling of multilayer laser solid freeform fabrication of nickel alloy 625 powder mixed with nano-CeO2 on AISI 4140

Gas turbine blades, turbine shafts and centrifugal compressor impellers are often damaged by erosion and/or corrosion. By laser cladding technique, a coating layer can be deposited on the base material in order to rebuild, repair and improve anti-erosion or anti-corrosion properties of the sensitive machine parts. In this paper, a three-dimensional finite element modeling of the laser solid freeform fabrication (LSFF) process for nickel alloy 625 powder mixed with nano-CeO2 on AISI 4140 steel is extensively studied. Using Comsol Multiphysics software and the finite element method (FEM), the heat transfer equation, moving mesh equation and stress tensor are numerically solved. The dynamic geometry of the molten zone is studied by a 3D moving mesh based on Arbitrary Lagrangian-Eulerian (ALE) module. Clad shape, temperature distribution and stress fields are obtained. The effects of preheating as well as addition of nano-CeO2 are investigated. Dependence of the clad height on the scanning velocity of the laser is also studied.