Research On High Temperature Rheological Behavior And Proceesing Map Of GH4169 Revert Alloy

GH4169 superalloy demonstrates excellent high temperature strength, good plasticity, fatigue as well as anti-corrosion properties, hence, it is widely used in the field of aerospace,and has become one kind of the most used superalloy. However,only about 30% of the alloy are available for industrial production after processing work, others exists in the form of sprue, stub bar and riser,the amount of these returns is as high as 70%, which resulting in a waste of resources. With the purpose to conserve resources and reduce the production cost, this paper studied the effect of proportion of added revert alloy on the segregation, microstructure and mechanical properties of GH4169 superalloy. Besides, research on the effect of different adding revert alloy on high temperature rheological behavior of GH4169 through the thermal simulation experiment, and on this basis to establish the thermal deformation constitutive equation and processing map of GH4169 revert alloy, to provide a guidance of recycling. The data of the compression test and the thermal simulation experiment include microstructure were analyzed,the results shows as follows.(1)There is no significant influence on segregation of GH4169 superalloy with different proportion of revert alloy added, content of N, O elements are increased,but this increasing is not linear to the proportion of revert alloy.(2)N, O elements increasing the amount of inclusions in GH4169 superalloy,which improve the segregation of Nb element, caused the aggregation and coarsening of Laves phase, and finally resulting the decrease of yield strength. The yield strength first increased and then declined slightly in both high temperature and room temperature, generally, shows an increasing trend with the increase of the revert alloy in GH4169.(3)The thermal deformation constitutive equation of GH4169 revert alloy can be described by the revised hyperbolic sine model. The activation energy Q of thermal deformation is 412.24KJ/mol.The constitutive equation is established.(4)The processing map of GH4169 revert alloy is established through the thermal simulation experiment, according to the map and requirements of product quality, forging process parameter are given: the strain rate is 10-3~10-2.5s-1, the deformation temperature is 1080~1150?.(5)The microstructure of the thermal deformation samples which shows rheological instability on processing map are analyzed, combined with elemental analysis results, conclusion that adding revert alloy increased the quantity of microporosities, which can growth into micro-cracks, and lead to rheological instability in GH4169 revert alloy.