Applying Stereological Characterisation to the Solidification Structure of Single Crystal Alloys to Deduce the 3D Macroscopic Solid/Liquid Interface Shape

Single crystals are a continuous unbroken solid crystal lattice with no grain boundaries. They find a wide range of applications, from semi-conductors, optoelectronics, to applications in aerospace engines. Primary spacing is a key phenomenon during single crystal solidification as it determines microsegregation, defect formation, and final material performance. In this work, an automatic, standardised, and comprehensive stereological single crystal characterisation methodology is applied to two sections of a CMSX-10® Ni-base superalloy bar. The Shape-Limited Primary Spacing methodology rapidly and accurately determines dendritic centres, packing pattern, and local primary spacing distribution within these bulk microstructures. Using the relationship between the radial variation of local primary spacing and isotherm curvature, the SLPS methodology has enabled the post-mortem reconstruction of the 3D macroscopic solid/liquid interface shape.