Research On Deforming Properties Of Superalloy GH4169

Superalloy GH4169has a predominant position in aeronautical and aerospace industries as structural materials, since this superalloy exhibits excellent properties and has wide application. However, there are lots of difficulties in hot working of superalloy GH4169. For example, the flow stresses are high, the suitable deformation temperature range is too narrow, and mixed microstructures is prone to occur which is detrimental to its mechanical performance. In this thesis, the hot deformation behavior of the GH4169alloy has been studied by means of hot compression deformation tests. The mechanical behaviour, the microstructure evolution behavior and the hot working chart of the GH4169alloy was analyzed. This thesis also simulated the extrusion and rolling process of GH4169alloy blade with Deform software and studied the simulation results in different parameters. The following research results and conclusions are mainly included:(1) In this thesis, the high temperature thermal simulation compression experiment of GH4169is designed, and the exact true stress-strain curve of GH4169is got. The relationship between the flow stress and the deformation Parameters is obtained. A high-temperature constitutive relationship which is to provide reliable mathematical model for accurate finite element simulation has been established on the basis of Zener-Hollomon equation. The model of deformation resistance of superalloy GH4169has been established; the calculated result agreed well with the experimental result and therefore validates the validity of the equation.(2) The microstructure evolution of the GH4169alloy during hot deformation is analyzed by electron back-scattered diffraction (EBSD) technique, optical microscope and transmission electron microscope (TEM) observations. The dependence of precipitated phase8and the volume fraction of the dynamic recrystallized grain on the deformation parameters are also analyzed. The dynamic recrystallization model during the hot deformation of the alloy is constituted.(3) According to the data obtained in thermal simulation compression experiment, based on the Dynamic Material Modeling, introducing Prasad plastic instability criterion to calculate the plastic instability area, the hot working chart can be got. This provides advantageous principle for the molding technological design of the alloy.(4) The microstructure evolution Precipitation regularity of GH4169alloy in different process conditions is analyzed; further understand the strengthening mechanism of the alloy.(5) The extrusion and rolling process of the GH4169alloy blade have been simulated with Deform software. The distribution of variables, e.g. temperature, effective stress and effective strain are studied in different parameters. Provides reference molding process optimization of the alloy。...