Wall-Thickness-Related Solidification Microstructure Variations in Domed Ni–Co–W Castings: Modelling and Experiment

Controlling variations in solidification microstructures, dependent on thermal and geometry factors, is essential for achieving uniform properties in castings with intricate shapes. This study investigates the solidification microstructure variations and their correlation with wall-thickness in Ni–Co–W castings with a domed plate shape. Through integrating the cellular automaton finite element (CA-FE) method with experimental observations, material parameters for reliable solidification simulations of the novel high-density Ni–Co–W alloy are determined. The formation of cellular/dendritic microstructures is found closely related to the ratio of temperature gradient ( \(G\) $G$ ) to root of solidification velocity ( \(\sqrt{\text{V}}\) $\sqrt{\text{V}}$ ) ( \(G/\sqrt{\text{V}}\) $G/\sqrt{\text{V}}$ ). Specifically, the influences of wall-thickness and ingate on the microscopic- and mesoscopic-scale solidification morphologies of the castings are elucidated by analyzing grain nucleation and growth characteristics. The quantitative consistency between modelling and experiments facilitates the rational design of complex-shaped Ni–Co–W castings with controlled microstructure variations using a computational-driven approach.