Effect of Pouring System on Microstructure and Properties of K4750 Alloy

K4750 alloy is a new cast nickel-based superallos Abstrxcellent mechanical properties at 700-750 degrees C and is expected to replace K4169 alloy. However, the tensile plasticity of K4750 alloy n temperature fluctuates, and the relationship among room temperature tensile properties, solidification microstructure, and casting3 meters is still unclear for this alloy. In this work. Kwds K4750 alloy test bars were prepared with various casting temperatures and shell cooling conditions, and tested at room temperat Juniaxial tension. Sensitivity of the alloy's room temperature tensile properties to changes in casting temperature and shell cooling 13 as evaluated, and the mechanism was elucidated by microstructure characterization Results show that the grain size of alloy drops significantly with decreasing casting temperature, and the yield strength of the alloy slightly increases while the plasticity remains stable. When the cooling rate of the shell decreases, the fracture elongation of the alloy decreases significar room temperature. This is mainly because the cooling condition of mold shell significan Addrets the precipitation characteristic Auth c carbides. When the cooling rate is low, MC carbides tend to precipitate at grain bound n coarse and strip-like shapes. A13 ides are prone to internal cracks under stress, accelerating the intergranular failure of m13 and reducing the plasticity of alloy order to optimize the tensile properties of K4750 alloy at room temperature, more attention should be paid to the cooling rate of mold shell after casting and the precipitation morphology of intergranular carbides, prohibiting the formation of coarse intergranular carbides to improve the grain boundary plasticity of the alloy.