Solidification behaviour of single crystalline nickel based superalloys


Ni-based superalloys are widely used to fabricate turbine blades of aero-engines and stationary gas turbines. In the nickel-based superalloys, grains with <001> orientation aligned parallel to the temperature gradient have the fastest growth rate and overgrow the slower growing orientations. The morphology of solid-liquid interface in directionally solidified superalloys can be related to the G/V ratio, where G is the temperature gradient in the melt ahead of the solidifying front and V is the solidification rate. Depending on solidification parameters, nickel based single crystalline superalloys can grow on planar, cellular or dendritic interface.


  1. To prepare single crystalline nickel based CMSX-4 superalloy with defined microstructure using directional solidification in Bridgman type apparatus.
  2. To study solidification behavior of CMSX-4 superalloy at steady-state conditions.
  3. To study columnar to equiaxed transition (CET) of CMSX-4 at non-steady conditions using power down technique and constant cooling rates.


Monokrystal CMSX4OM micrograph showing the typical distribution of dendrites in single crystalline sample on transverse section
Mikrostruktura CMSX4SEM microstructure shows ordered γ’ (Ni3(Al,Ti)) precipitates coherently embedded in γ (Ni base solid solution) matrix with face centered cubic crystal structure
Rozhrania 0.5cm za h 
Rozhrania 1cm za h 
Dendritic solid-liquid interface prepared by quenching during directional solidification, longitudinal section
CET CMSX4 Columnar to equiaxed transition in CMSX-4 superalloy prepared at unsteady state growth conditions

Additional reading

LAPIN, J. - PELACHOVÁ, T. - ADAMČÍKOVÁ, A. - ZEYTIN, H.K. Solidification behavior of Ni-based CMSX-4 superalloy studied by directional solidification. In 5th International Conference “Mechanical Technologies and Structural Materials”, MTSM2015, 2015, Croatian society for mechanical technologies, c/o FESB, Ruđera Boškovića 32, 21000 Split, Croatia, ISSN 1847/7917, pp. 93-100. ISSN 1847-7917.

LAPIN, J. - GEBURA, M. - PELACHOVÁ, T. - NAZMY, M. Coarsening kinetics of cuboidal γ’ precipitates in single crystal nickel base superalloy CMSX-4. In KOVOVE MATER, 2008, vol.46, pp. 313-322. (Current Contents, Scopus, WOS). ISSN 0023-432X.

GEBURA, M. - LAPIN, J. Morphological changes of γ’ in Ni-based superalloy during long-term ageing. In 17th International Conference on Metallurgy and Materials, METAL 2008, [online], 2008, Červený zámek, Hradec nad Moravicí, Tanger Ltd, pp. 311-317. ISBN:978-80-87294-10-9.

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