Effects Of ? Phase And Pulse Current On Tensile Deformation Behavior Of GH4169 Superalloy At High Temperature

With the rapid development of the aerospace industry,the requirement of turbine inlet temperature is increasing,and the working condition of the superalloy becomes harder and harder.High alloying can effectively improve the high temperature strength of the alloys,but it leads to difficult deforming.As a type of energy instantaneous inputted,a lot of achievements have been obtained in the research of plastic working of some metallic materials such as Mg alloy,Ti alloy and stainless steel utilizing the electroplastic effect of pulsing current.But all these are based on the reasonably control of microstructure,otherwise no effects or even in opposite.The researches showed that the content,morphology and distribution of the ? phase can have an effect on the mechanical properties and deformation behavior of GH4169 superalloy.In the present study,two kinds of microstructures with or without ? phase were obtained by different heat treatments for GH4169 superalloy."In situ pulse current tensile testing at high temperature " and " high temperature tensile testing after pulse current aging" were carried out for the alloy with two kinds of microstructures.The effects and mechanism of 8 phase and pulse current on the high temperature deforming and dynamic recrystallization behavior of the alloy were investigated.And the mechanism of electric effect on the high temperature deformation behavior of the alloy was also studied.The results showed that the deformation resistance of GH4169 superalloy decreased with the application of pulse current,and the reduction of deformation resistance increased with the increasing of pulse current frequency.8 phase could restrain the dynamic recrystallization behavior of alloys.Compared with the alloy without ? phase,recrystallization grain size of the alloy with 8 phase was smaller and the degree of recrystallization was low.At the same time,the tensile ductility of the GH4169 alloy with ? phase at 800? was better and the elongation was higher.After the pulse current aging treatment,the content of ?' phase increased in the alloy without ? phase,and short rod ? phase was transformed into long needle shape in the alloy with ? phase.The tensile strength of alloy with both kinds of microstructures was improved.By the applied pulse current,the electronic wind force and mechanical force could accelerate dislocation movement and reduce deformation resistance of the alloys during tensile deformation.The ? phase could provide nucleation sites for recrystallization during tensile deformation,which increased the nucleation rate.But it hindered the migration of recrystallization grain boundaries.Pulse current aging could accelerate the diffusion of solute atoms,which made the content of ?"phase increase by 12.5%in the alloy without ? phase,which leads to the dislocation tangle during deformation,then the tensile strength of the alloy could be improved.