Papers by Keyword: IN718 Alloy

Abstract: A coupled numerical simulation between thermal-mechanical and microstructure evolution was realized through embedding the developed user subroutines into the FEM software DEFORM-3D system. Then the dynamic recrystallization fraction and average grain size of In718 alloy in cylindrical cup backward extrusion with different parameters was solved and analyzed. The complete dynamic recrystallization occurs in the middle of cylinder wall and the grain size is the finest. However, the grain size of top of cylinder wall changes less because of the less plastic deformation. Furthermore, higher speed of punch is useful to the DRX but it is not enough time to occur dynamic recrystallization completely with much higher speed of punch. In spite of more recrystallization occurring in the bottom, the grains grow in the cylinder wall so that much higher temperature goes against improving finer and uniform of grain size. Therefore, it is better for obtaining finer and uniform grain size with 1000(°C)-1050(°C) and 5(mm/s) in In718 alloy cylindrical cup backward extrusion according to the research.

Abstract: The pulse current was performed on the IN718 alloy during tensile test at room temperature and elevated temperature in the present study. The effect of pulse current on the deformation behavior of the alloy and the mechanisms were investigated. The results show that the deformation resistance decreases and the elongation increases significantly of IN718 alloy during tensile test at room temperature and 1073 K with the increase of pulse current. And the effect of pulse current on the strength and plasticity of the alloy increases as pulse current energy increases. The electroplastic effect of pulse current can promote the dislocation motion, and thus decrease the deformation resistance of the alloy during the tensile deformation. The pulse current reduces the starting temperature of recrystallization, promotes the recrystalllization nucleation, and thus makes it possible that the dynamic recrystallization would occur at lower temperature than that in the conventional temperature field. This is the main reason for the decrease of deformation resistance and the increase of plastic deformation ability of IN718 alloy under pulse current.