Additive manufacturing of multi-material assembly

Additive manufacturing of multi-material assembly

 

Amela KUSURAN^a,b, David MERCS^b, Ludovic VITU^a, Geoffrey DARUT^a, Marie-Pierre PLANCHE^a

 

The objective of this work is to assemble an aluminum alloy to a steel allowing therefore to reduce the final mass of this assembly. Doing that, cold spray is considered as an efficient solution. Surfaces are previously prepared with a texturing laser to improve the adhesion of the coating on the substrate. Deposits are slightly rough Ra < 10 µm, the porosity is less than 1% and the adhesion is higher than 80 MPa for textured surfaces. These high values are also due to the high filling rates in holes (100% for steel and 65% for aluminum alloy). Shear values obtained through the combination of laser texturing and cold spray for multi-material assembly are of 90 MPa (a heat treatment of 3h at 300°C applied on the joining point improves mechanical strength and increases it by three). By analogy with linear joining methods such as Laser Welding (190 MPa), the values obtained in uniaxial tension by this assembly method are significantly lower (around 50 MPa). It can be explained by the nature of the joining bead, which is made of aluminum alloy.