Product Code: ICA11_709

2D Finite Element Modeling of Heat Transfer and Fluid Flow during Multi Layered DMD Laser Process
Authors:
Simon Morville, LIMATB; Lorient Cedex France
Muriel Carin, LIMATB; Lorient Cedex France
Denis Carron, LIMATB; Lorient Cedex France
Philippe Le Masson, LIMATB; Lorient Cedex France
Patrice Peyre, PIMM; Paris France
Myriam Gharbi, PIMM; Paris
Cyril Gorny, PIMM; -
Remy Fabbro, PIMM; Paris France
Presented at ICALEO 2011

Derived from laser cladding, the Direct Metal Deposition (DMD) laser process is based upon a laser beam powder melt pool interaction, and enables the manufacturing of complex 3D shapes much faster than conventional processes. However, the surface finish remains critical, and DMD parts usually necessitate post-machining steps. Within this context, the focus of our work is to improve the understanding of the phenomenon responsible for deleterious surface finish by using numerical simulation. Mass, momentum, and energy conservation equations are solved using COMSOL Multiphysics® in a 2D transient model including filler material with surface tension and thermocapillary effects on the free surface. The dynamic shape of the molten zone is explicitly described by a moving mesh based on an Arbitrary Lagrangian Eulerian method (ALE). This model is used to analyze the influence of the process parameters, such as laser power, scanning speed, and powder mass flow rate, on the melt pool behavior. The simulations of a single layer and multilayers are presented. The numerical results are compared with experimental data, in terms of layer height, melt pool length, and depth of penetration, obtained from high speed camera. The experiments are carried out on a widely-used aeronautical alloy (Ti-6Al-4V) using a Nd:YAG laser.