Direct laser fabrication process with coaxial powder projection of 316L steel. Geometrical characteristics and microstructure characterization of wall structures

Hussam El Cheikh (1) , Bruno Courant (1) , Samuel Branchu (1) , Xiaowei Huang (2) , Jean-Yves Hascoët (3) , Ronald Guillén (1)

1 E3M - État Mécanique et Microstructure des Matériaux
2 LAMPA - Laboratoire Angevin de Mécanique, Procédés et InnovAtion
3 IRCCyN - Institut de Recherche en Communications et en Cybernétique de Nantes

Direct Laser Fabrication is a promising manufacturing technology. A moving laser beam heats a coaxially delivered powder in a gas jet through nozzle in order to fabricate an end-use part directly. The clad geometry is an important process characteristic. In this work, different velocities and different laser shift-distances between two successive layers are used to build walls. For each condition, 1, 3, 5 and 10 layers walls are analyzed, showing the domain of a success and optimal construction. A relationship between the process parameters and the wall height is obtained with a good correlation. In addition a linear relationship relates the wall height to the number of layers. Columnar dendrites are observed on the bottom laser clad and equiaxed grains on the top one. Microhardness measurements show a homogeneous microhardness in each layer but a higher microhardness in the first one.

Mots clés: Direct Laser Fabrication; 316L stainless steel; Laser track geometry; Microstructure; Microhardness

Domaines: Mécanique [physics.med-ph]; Matériaux

Hussam El Cheikh, Bruno Courant, Samuel Branchu, Xiaowei Huang, Jean-Yves Hascoët, et al.. Direct laser fabrication process with coaxial powder projection of 316L steel. Geometrical characteristics and microstructure characterization of wall structures. Optics and Lasers in Engineering, 2012, 50 (12), pp.1779-1784. ⟨10.1016/j.optlaseng.2012.07.002⟩. ⟨hal-01006750⟩