Impact of Aluminium and Cooling Conditions on Silicon Distribution in High Si-SGI by Performing 3D-Microstructure Simulations

Solid-solution-strengthened ferritic ductile ironSolid-solution-strengthened ferritic ductile iron (SSFDI) exhibits a superior ratio of tensile strengthTensile strength to elongation compared to conventional ductile ironIron grades, up to a maximum silicon content of 4.3 wt%. Beyond this threshold, SSFDI experiences a sudden decline in ultimate tensile strengthTensile strength and elongation at fracture. This degradation can be attributed to negative silicon segregationSegregation during solidificationSolidification, with the highest silicon concentration observed near the graphite nodules. The resulting high silicon concentration promotes long or short-range ordering of ironIron and silicon, leading to the formation of superstructures such as BCC_B2 and D03. These superstructures hinder dislocation mobilityDislocation mobility and contribute to the abrupt fracture of the materialMaterials. This research investigates the influence of aluminium additionAluminium addition and cooling conditionsCooling conditions on silicon segregationSegregation profile in EN-GJS-500–14 through phase field simulationsPhase field simulations. The phase field method allows for the modelling of microstructural evolutionMicrostructural evolution during solidificationSolidification till solid state transformation. By systematically varying the composition of the alloy and adjusting the cooling parameters, the simulation results provide valuable insights into the mechanisms underlying silicon homogenizationSilicon homogenization and the mitigation of superstructure formation. The findings from this study contribute to a deeper understanding of the microstructural evolutionMicrostructural evolution in high silicon ductile ironIron and provide guidance for optimizing the alloy composition and cooling conditionsCooling conditions to facilitate silicon homogenizationSilicon homogenization. By effectively suppressing the formation of superstructures, it is anticipated that the mechanical propertiesMechanical properties of SSFDI can be enhanced, potentially expanding its application range in various industries.