Effect of solidification parameters on the secondary dendrite arm spacing in MAR M-247 superalloy determined by a novel approach

The effect of solidification parameters on the secondary dendrite arm spacing in a MAR-M247 Ni-based superalloy has been studied by a novel approach, based on physical simulation of melting/solidification experiment with a constant cooling rate and variable temperature gradient. The applied experimental method proved to be efficient 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 secondary dendrite arm spacing is better related to the solidification rate than to the cooling rate in the case when significant variations of thermal parameters during the solidification process occur