Pre-treatment and Coatability of Additive Manufactured Components Made by Means of Selective Laser Melting

Additive manufacturing (AM) has already been evolved into a promising manufacturing technique. In order to achieve the performance of conventionally manufactured components, additively manufactured components must meet at least the same mechanical and physical requirements. Due to the layer-wise building process, the properties of additively manufactured components differ from that of bulk materials.

Within the scope of this study, the Selective Laser Melting (SLM) technology was used to manufacture specimens which serve as substrates for a subsequent coating process. An Inconel 718 and a 316L alloy served as AM feedstock. Thermal and mechanical post-treatments were applied to the AM sample types and rated with respect to the successive thermal spraying process. The produced AM sample types were examined in their initial state as well as under post-treated conditions. Within this context, the resulting surface roughness and residual stresses were analyzed. Different AM sample types were coated by means of High Velocity Oxy-Fuel (HVOF) spraying and Atmospheric Plasma Spraying (APS). The interface between the thermally sprayed coating and the AM substrate as well as the coating morphology are metallographically investigated. Tensile adhesion tests were conducted to scrutinize the bond strength of the coating to the AM substrate.