The element segregation and the accompanied phase formation along the solidification path can be crucial for defect formation, e.g. hot cracking, but is also important for the material performance or the design of subsequent processing steps like heat treatment.

In this presentation, we will discuss results from phase-field simulations in comparison to experimental results (e.g. TEM and atom probe) for the Ni-based superalloy CM247LC. The phase-field model is linked to a thermodynamic CALPHAD database and therefore takes into account the full chemistry, i.e. the major alloying and trace elements C, Cr, Co, W, Mo, Ta, Al, Ti, Hf, B and Zr and the phases liquid, fcc, MC-carbide, gamma’, µ-phase, BCC_B2, the boride MB2_C32 together with the low temperature carbides M23C6, M12C and M6C. The simulations support a proper interpretation of the type, chemistry and distribution of precipitates seen in SEM or TEM images.

Simulated phase fractions and the microsegregation pattern will be quantitatively compared for three different process conditions owing a variation of the average cooling rates between 65,000 K/s and 570,000 K/s. Experimental results show a significantly different crack density for the three conditions. Simulations show correlating trends, e.g. for the formation of MC-carbides or for the solidification interval. However, besides the varying primary dendrite spacing, the differences in integral phase fractions or the solidification interval are rather small and could not conclusively explain the hot cracking tendency.