Parametric studies of multi-material laser densification

Fabrication of multi-material components via a laser-assisted layer-by-layer fabrication process has been numerically simulated and analyzed using a three-dimensional thermo-mechanical model. Effects of the chamber preheating temperature, laser scanning rate, initial porosity and thickness of each powder layer on the out-of-plane warping and residual thermal stresses of a nickel/porcelain workpiece have been investigated. It is found that warping and residual thermal stresses of the laser-densified multi-material workpiece are more sensitive to the chamber preheating temperature and the thickness of each powder layer than to the laser scanning rate and the initial porosity of the powder layer. The major mechanism responsible for these phenomena is identified to be related to the change of the temperature gradient induced by these laser processing parameters.