Laser-based manufacturing of components using materials with high cracking susceptibility

Abstract

Laser metal deposition has been already introduced in various industrial branches, as aviation, energy, medical technology, or tooling. Depending on process conditions of the specific application, powder, wire, or even strips can be used as filler material to coat, and to refurbish as well as to manufacture parts and functional components. Independent from the chosen type of filler material, the deposition has to be in line with specific requirements such as the allowed appearance of porosity, delamination, dilution, or cracking. The latter often becomes rather challenging due to high thermal gradients caused by typical laser-related high energy densities. Relief can be found by hybrid processing as well as suited process regimes yielding in suitable tailored temperature states and crack-free material deposition. Within this paper, such tailored solutions for the manufacturing and processing of materials with a high hot and cold cracking susceptibility such as nickel-based superalloys and alloys based on titanium aluminides are presented. Critical impacts like heating and cooling based on the analysis of melt pool flow and the morphology of solidification are considered. The authors present possibilities to influence, control, and monitor the process. The mechanical properties of corresponding additive manufactured demonstrators will be validated on the basis of destructive and nondestructive testing.