Advertisement

Laser Cladding for Crack Repair of CMSX-4 Single-Crystalline Turbine Parts

  • Boris Rottwinkel
  • Christian Nölke
  • Stefan Kaierle
  • Volker Wesling
Article

Abstract

The increase of the lifetime of modern single crystalline (SX) turbine blades is of high economic priority. The currently available repair methods using polycrystalline cladding of the damaged area do not address the issue of monocrystallinity and are restricted to few areas of the blade. The tip area of the blade is most prone to damage and undergoes the most wear, erosion and cracking during its lifetime. To repair such defects, the common procedure is to remove the whole tip with the damaged area and rebuild it by applying a polycrystalline solidification of the material. The repair of small cracks is conducted in the same way. To reduce repair cost, the investigation of a manufacturing process to repair these cracked areas while maintaining single-crystal solidification is of high interest as this does not diminish material properties and thereby its lifetime. To establish this single-crystal solidification, the realization of a directed temperature gradient is needed. The initial scope of this work is the computational prediction of the temperature field that arises and its verification during the process. The laser cladding process of CMSX-4 substrates was simulated and the necessary parameters calculated. These parameters were then applied to notched substrates and their microstructures analyzed. Starting with a simulation of the temperature field using ANSYS®, a process to repair parts of single crystalline nickel-based alloys was developed. It could be shown that damages to the tip area and cracks can be repaired by establishing a specific temperature gradient during the repair process in order to control the solidification process.

Keywords

CMSX-4 Single crystal Laser cladding Blade repair 

Notes

Acknowledgments

The work presented was supported by the German Research Foundation (DFG) within the Collaborative Research Centre (SFB 871 “Product Regeneration”). The authors would like to thank the DFG for their support.

References

  1. 1.
    Gäumann, M., Bezençon, C., Canalis, P., Kurz, W.: Single-crystal laser deposition of superalloys: processing-microstructure maps. Acta Mater. 49(6), 1051–1062 (2001)CrossRefGoogle Scholar
  2. 2.
    Acharya, R., Bansal, R., Gambone, J. J., Das, S.: A Coupled thermal, fluid flow, and solidification model for the processing of single-crystal alloy CMSX-4 through scanning laser epitaxy for turbine engine hot-section component repair (Part I). Metallurgic. Mater. Trans. B, 45(6) (2014)Google Scholar
  3. 3.
    Acharya, R., Bansal, R., Gambone, J.J., Das, S.: A microstructure evolution model for the processing of single-crystal alloy CMSX-4 through scanning laser epitaxy for turbine engine hot-section component repair (Part II). Metallurgic. Mater. Trans. B, 45(6) (2014)Google Scholar
  4. 4.
    Liu, Z., Qi, H.: Effects of substrate crystallographic orientations on crystal growth and microstructure formation in laser powder deposition of nickel-based superalloy. Acta Mater. (2015)Google Scholar
  5. 5.
    Liu, Z., Qi, H.: Numerical simulation of transport phenomena for a double-layer laser powder deposition of single-crystal superalloy. 45 (2014)Google Scholar
  6. 6.
    Liu, Z., Qi, H., Jiang, L.: Control of crystal orientation and continuous growth through inclination of coaxial nozzle in laser powder deposition of single-crystal superalloy. 230, 177–186 (2016)Google Scholar
  7. 7.
    Liu, W., DuPont, J.N.: Effects of melt-pool geometry on crystal growth and microstructure development in laser surface-melted superalloy single crystals. Acta Mater. 52(16), 4833–4847 (2004)Google Scholar
  8. 8.
    Liu, W., DuPont, J.N.: Effects of substrate crystallographic orientations on crystal growth and microstructure development in laser surface-melted superalloy single crystals. mathematical modeling of single-crystal growth in a melt pool (Part II). Acta Mater. 53(5), 1545–1558 (2005)CrossRefGoogle Scholar
  9. 9.
    Wang, L., Wang, N., Yao, W.J., Zheng, Y.P.: Effect of substrate orientation on the columnar-to-equiaxed transition in laser surface remelted single crystal superalloys. Acta Mater. 88, 283–292 (2015)CrossRefGoogle Scholar
  10. 10.
    Wang, L., Wang, N.: Effect of substrate orientation on the formation of equiaxed stray grains in laser surface remelted single crystal superalloys. Experiment. Investig. 104, 250–258 (2016)Google Scholar
  11. 11.
    Mokadem, S., Bezençon, C., Hauert, A., Jacot, A., Kurz, W.: Laser repair of superalloy single crystals with varying substrate orientations. Metallurgic. Mater. Trans. A: Phys. Metallur. Mater. Sci. 38 A(7), 1500–1510 (2007)CrossRefGoogle Scholar
  12. 12.
    Vitek, J.M.: The effect of welding conditions on stray grain formation in single crystal welds - theoretical analysis. Acta Mater. 53(1), 53–67 (2005)MathSciNetCrossRefGoogle Scholar
  13. 13.
    Gäumann, M., Trivedi, R., Kurz, W.: Nucleation ahead of the advancing interface in directional solidification. Mater. Sci. Eng. A 226–228, 763–769 (1997)CrossRefGoogle Scholar
  14. 14.
    Hunt, J.D.: Steady state columnar and equiaxed growth of dendrites and eutectic. Mater. Sci. Eng. 65(1), 75–83 (1984)CrossRefGoogle Scholar
  15. 15.
    Gäumann, M., Henry, S., Cléton, F., Wagnière, J.-D., Kurz, W.: Epitaxial laser metal forming: analysis of microstructure formation. Mater. Sci. Eng. A 271(1-2), 232–241 (1999)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2016

Authors and Affiliations

  1. 1.Laser Zentrum Hannover e.V.HannoverGermany

Personalised recommendations