Research On The Influences Of Rare Earth On Hot-processing And Deforming Properties Of GH4169 Alloy

As a nickel-base super-alloy,GH4169 alloy has been widely applied in many areas owning to its excellent structures and mechanical properties.This alloy has a predominant position by terms of consumption in all super-alloys.During hot-working process,GH4169 alloy is difficult to process because of the sensitivity of this alloy.In this thesis,the hot deformation behavior of GH4169 alloy is systematically investigated by single pass thermo-simulation experiment on GH4169 after adding rare earth(RE),analyzing the hot deformation behavior,the processing map and the microstructure evolution behavior.Together with the blade extrusion molding design of GH4169 alloy through regarding elevated temperatures constitutive relationships as mathematical model,the effect of different process parameters on blade molding process is studied.The detailed conclusions and achievements are summarized as follows:(1)Based on the high temperature thermal simulation compression experiment of the alloy,which is obtained from forged and solid-solution treated GH4169 alloy after adding rare earth,the exact true stress-strain curve of GH4169 alloy is got.From this curve,how the thermal processing parameters will impact the flow stress is obtained.Then,the constitutive equation for flow stress at high temperature is constructed on the basis of Zener-Hollomon equation,compared with the constitutive equation of GH4169 alloy without RE,which provided a quite exact mathematical model for finite-element simulation.(2)Based on processing map theory of dynamic material modeling(DMM),the hot performing process map of GH4169 alloy under different deformation is drawn.After analyzing the obtained processing map of both GH4169 alloy with RE and without RE,the thermal processing parameters are optimized.Then,the microstructure evolvement regularity of GH4169 alloy is investigated through observing the structure of GH4169 under different thermal processing parameters.Combining processing map,the relationship between different region of processing map and its structure evolvement is analyzed.(3)Based on the constitutive equation at high temperature,blade extrusion molding process of GH4169 alloy is simulated by finite-element software Deform-3D,analyzing the distribution rule of blade temperature before and after adding RE,effective stress and effective strain under different thermal processing parameters.According to the distribution rule,the optimal process parameters of blade extrusion molding process of GH4169 alloy are obtained,which provide reference for practical thermal processing of this alloy.