High Velocity Air Fuel Spraying for Metal Additive Manufacturing - A Study on Copper.

Owing to its reflectivity, Copper manufacturing has always been challenging through laser-based additive manufacturing. In this study, we demonstrate additive/bulk manufacturing of copper using high velocity air fuel (HVAF) spray technology, an emerging variant in the thermal spray family. Rapid deposition of millimeter scale copper parts with good mechanical integrity and decent ductility, comparable to that of cold spray, has been shown feasible. The mechanical properties measured along different built directions showed no significance to be considered anisotropic. Electron backscattered diffraction analysis revealed the possibility of developing favorable bimodal grain distribution with a high volume fraction of ultrafine grains (>50%). However, the intersplat porosities and continuous pores were found to be detrimental despite the low overall porosity. HVAF technology demonstrates great potential and appears to be a promising process methodology for bulk/additive manufacturing of metals with a rapid production rate. [ABSTRACT FROM AUTHOR]