Semi-solid plasticity and deformation control of superalloy investment casting

The deformation in superalloy investment casting under thermal-mechanical coupled stress results in significant waste of materials and energy. In order to accurately predict the deformation of castings, it is crucial to develop and apply mechanical models of both alloy and shell. The elastoplastic behavior of superalloy in a semi-solid zone is critical to the deformation during solidification. This study focuses specifically on the deformation of ring-to-ring castings with Ni-based superalloy K4169. To obtain the thermal-mechanical behavior of K4169 from solid region to semi-solid zone, physical simulated uniaxial compression is performed. The measured yield stress and plastic modulus are imported into the database for numerical simulation. Different thermal-mechanical models of both alloy and shell are compared. With elastoplastic model for alloy, considering the deformability of shell with elastic model, the maximum error is limited to 0.34 mm. Among groups of processing parameters, the deformation reaches the minimum when the initial temperature of alloy and shell are 1500 \(^{\circ }\)C and 900 \(^{\circ }\)C. The research on the semi-solid performance of the alloy and the development of thermal-mechanical models can provide theoretical insights for predicting deformation. Moreover, the research methodology holds promise for dimensional control of castings and can be transported to dimensional control problems upon solidification process with different kinds of materials and castings.