W. L. Weingaertner
L. Schweitzer
B. Rottwinkel
C. Nölke
S. Kaierle
V. Wesling

Single-crystal (SX) laser cladding of CMSX-4

ABCM International Congress of Manufacturing Engineering (COBEM)
18.-22. Mai
Salvador
2015
Type: Konferenzbeitrag
Abstract
The prosperity and widespread use of aviation as a civil national and international transport requires seriousness in the aircraft conditioning. Preventive maintenance is the key to avoid disasters. For that, the check of engines is essential, which corresponds to higher reconditioning costs. Due to elevated temperature and pressure working conditions there is usually a significant number of scrap rated parts in the high pressure turbine segment. These parts consist mainly of single crystal casted parts, which withstand high temperature levels, but are particularly costly compared to polycrystalline parts. Consequently there is an interest in developing techniques for an efficient repair of these single crystal turbine components. The common damages of these parts are erosion and crack formations that require refurbishing. A recognized method for the repair of cracks in SX turbine blades has to be developed. The proposal of this work involves the application of laser cladding with powder injection, due to characteristics such as localized treatment and control of the material injected. This process is particularly suitable due to its flexibility and low dilution levels. Based on that a laser cladding technique was developed to promote the SX repair of cracks and to allow an adequate reconstruction of the defect. A possibility to enable epitaxial cladding is to introduce a temperature gradient in order to guide the grain growth in the desired direction. To evaluate the main influences for the formation of a single crystal microstructure a parameter optimization was developed. This methodology is presented in this work, as well as a parameter optimization study.