Laser metal deposition of Ta-10W alloy based on annular laser cladding with internal wire feeding

Abstract

Laser metal deposition is a new type of laser forming technology with the advantages of small heat affected zone, low dilution rate and high bonding strength. Ta-10W is a high temperature refractory material, which often used in aerospace fields. However, the high melting point and thermal conductivity causes Ta-10W to be prone to cracks collapse during processing and forming. Annular laser cladding provides a feasible way to solve the contradiction between high temperature service performance and processing performance of Ta-10W due to its high energy density, freedom of direction and nearly 100% material utilization. In this paper, Ta-10W cladding layers without cracks and pores were successfully deposited on the Nb substrate based on the wire-annular laser cladding technology. The hardness of the cladding layer is 4 times that of the Nb substrate and the dilution rate is extremely low. The Ta-10W wire must be in the center of the annular laser, otherwise the cladding may fail to form. It is found that the larger the wire feeding speed results in the smaller the aspect ratio; while the larger scanning speed, defocus distance and laser power result in the larger aspect ratio. This work opens up a new path for the fabrication of refractory metals, which is significant for processing high temperature materials.