I. Buchbender
C. Hoff
J. Hermsdorf
V. Wesling
S. Kaierle

Single-crystal height extension by Laser Metal Deposition of CMSX-4

11th CIRP Conference on Photonic Technologies (LANE)
07.-10. September
Type: Konferenzbeitrag
The introduction of directionally solidified and single-crystal nickel-based superalloys have led to a higher thermal efficiency of engines by allowing for an increase in turbine inlet temperatures from 1000°C to 1400°C. These temperatures however lead to higher thermal stress and corrosive environments, resulting in a shorter life span. Previous work has shown the applicability of laser metal deposition (LMD) for the regeneration of these high value components, while maintaining primary crystalline orientation of single-crystal high pressure turbine blades. However, the processing of these materials by LMD poses several challenges, such as susceptibility to cracking, the formation of misoriented grains and low weldability. This paper examines deposition strategies to extend single-crystal height. While a continuous, meandering strategy shows the most promising percentage single-crystallinity results, an additional remelting step increases epitaxial deposition height. Apart from percentage single-crystallinity and deposition height, this study quantifies the effect of these strategies on cracking and the formation of misorientations.