A physical simulation study of the effect of thermal variations on the secondary dendrite arm spacing in a Ni-based superalloy

Abstract

The effect of thermal variations on the secondary dendrite arm spacing (SDAS) in a MAR-M247 Ni-based superalloy has been studied by a novel method based on a physical simulation of melting/solidification experiments with a constant cooling rate and variable temperature gradient. The method proved to be effective as it yielded a spread of microstructures corresponding to a range of well-controlled solidification rates in a single melting/solidification experiment. In addition, it has been demonstrated that SDAS is better related to the solidification rate than to the cooling rate in cases when significant variations of thermal parameters during the solidification process occur.

Keywords:

• physical simulation
• solidification
• Ni-based superalloy
• secondary dendrite arm spacing

Acknowledgements

This investigation was supported by the project VANCAST (EU, FP7, ERA-NET MATERA+). IS and SM acknowledge gratefully the Spanish Ministry of Economy and Competitiveness for funding through the Ramon y Cajal fellowships.