The Study On Mechanism For Critical Grain Growth Of The Extruded FGH4096 Alloy

In this paper,the extruded FGH4096 alloy for aeroengine turbine disk is used as the research object.The cylinder and double conical table specimens of the extruded FGH4096 alloy were subjected to compression deformation experiments at room temperature and high temperature and heat treatment experiments under different conditions.Numerical simulations of compression deformation experiments were performed.The deformation behavior of extruded FGH4096 alloy is analyzed,and the microstructure is observed in combination with numerical simulation equivalent strain distributions,and the phenomenon of critical grain growth for extruded FGH4096 alloy at room temperature and high temperature compression is studied.In order to solve the failure problem of aeroengine turbine disks in service and improve the reliability and safety of aeroengine,the critical grain growth window conditions are determined to optimize hot working process parameters,and mechanism of critical grain growth is clarified.The main research contents and results were obtained as follows:Through the room temperature compression and heat treatment experiments of the extruded and over-solution extruded FGH4096 alloy cylinder specimens,the true stress-true strain curves and numerical simulation curves are analyzed combined with the numerical simulation for room temperature compression,and they are in high agreement.The critical grain growth phenomena of room temperature compression for FGH4096 alloy cylinder specimens in two initial states are analyzed,and the critical grain growth window conditions are initially determined.The critical grain growth of FGH4096 alloy cylinder specimens in two initial states occurred within the range of critical equivalent strain 0.03-0.07 after compression at room temperature in 0.01mm/s and over-solution treatment at 1150? for 60s.Through the room temperature compression and heat treatment experiments of FGH4096 alloy double conical table specimens in two initial states,the actual load curve and numerical simulation curves are analyzed combined with the numerical simulation for room temperature compression,and they are in high agreement.The critical grain growth phenomena of room temperature compression for FGH4096 alloy double conical table specimens in two initial states are analyzed,and the extruded FGH4096 alloy with a larger initial grain size after compressed at room temperature has a larger critical grain size after a long period of over-solution treatment.The critical grain growth window conditions are accurately determined.The critical grain growth of FGH4096 alloy double conical table specimens in two initial states occurred within the range of critical equivalent strain 0.005-0.06 after compression at room temperature in 0.05mm/s and over-solution treatment at 1150? for 1h.The critical grain growth mechanism of extruded FGH4096 alloy at room temperature compression are analyzed.Through the high temperature compression and heat treatment experiments of the extruded FGH4096 alloy double conical table specimens,the actual load curve and numerical simulation curves are analyzed combined with the numerical simulation for high temperature compression,and they are in high agreement.The critical grain growth phenomena of high temperature compression for extruded FGH4096 alloy double conical table specimens are analyzed,and the critical grain growth window conditions are accurately determined.The distribution of the critical grain growth window conditions at high temperature compression are analyzed,and the critical grain growth mechanism of extruded FGH4096 alloy at high temperature compression was studied.