Feasibility of multilayer solid-state deposition via lateral friction surfacing for metal additive manufacturing

Abstract

Lateral friction surfacing is a novel solid-state deposition process in which the radial surface of the rotating consumable tool is forced into the substrate surface, facilitating material transfer. This technique is an excellent alternative to create thin and ultra-smooth metallic deposit layers for repairing damaged surfaces or improving corrosion and wear resistance. The lateral friction surfacing approach results in a deposition process with lower generated process temperatures than conventional friction surfacing, which leads to reducing thermal effects on the microstructures and mechanical properties of the deposits. In this study, the extent of material transfer to the substrate was explored via multiple passes of the tool in an effort to create multiple layers of deposited material. Two types of substrate plates with different surface roughness as well as two different strategies for employing the consumable tools were experimented. A comprehensive assessment through conducting real-time force measurement, surface roughness measurement, hardness testing, optical microscopy, infrared thermography, scanning electron microscopy, and EDS analysis was performed to characterize the process and the fabricated deposits. The thickness of the coating was found to vary through work material transfer to the substrate and reverse material transfer from the coating to the radial surface of the rod, resulting in an approximately steady-state deposit thickness. The reverse material transferring process from the coating to the radial surface of the rod through rubbing off the previously fabricated coatings limits plasticizing more consumable material and built-up material.