CuNiSiCr alloy parametrization for defect-free DED-LB coating with conventional fibre laser

Abstract

Copper alloys´ high thermal conductivity combined with the freeform capabilities of the additive manufacturing technologies, offer new opportunities in the design of aerospace components, such as thrust nozzles. However, the high reflectivity of copper alloys at the 1.076 µm wavelength range makes their manufacturing with conventional fibre lasers difficult. Therefore, an effective methodology for manufacturing CuNiSiCr-alloys with conventional fibre lasers is required.

For this purpose, the laser-based Directed Energy Deposition (DED-LB) process for depositing a CuNiSiCr-alloy is parametrized to ensure a defect-free operation of the final part. Through a design of experiments process, the optimum parameters are obtained and they are validated through the manufacturing of single clads and more complex geometries. During the tests, the melt-pool temperature and dimensions are monitored to increase the control over the manufacturing process and ensure process stability. Results show a high metallurgical integrity, which justifies the viability of fibre lasers to manufacture CuNiSiCr-alloys.