Microstructure Evolution Model Of7050Aluminum Alloy During Hot Compression Based On Cellular Automata Method

7050aluminum alloy is a typical high strength and high toughness structuralmaterials in aviation, because of its excellent mechanical properties, which is widelyused in the manufacture of important aircraft forging components, such as landing gearbulkheads, wing beams and brackets, which are important bearing structure.Macroscopic mechanical properties of the metal are determined by the microstructure,in the process of hot working, not only the macroscopical shape of the metal will bechanged, its microstructure will be changed too, such as dynamic recrystallization,dynamic recovery and so on. Therefore, it has a very important significance tounderstand and master the microstructure evolution of the metal in the thermoplasticdeformation to improve their overall performance and control the quality of the product.The traditional method to simulate the microstructure evolution is based on theexperiment, establishing phenomenological model described by the empirical formula.The microstructure evolution can only be analyzed qualitatively. Along with thedevelopment of computational materials science, people can build new model whichreflects microstructure evolution essentially. At present, Monte Carlo method, the Phase-Field method and Cellular Automata method are widely used to establish the newmodel. By comparing the advantages and disadvantages of the different methods,Cellular Automata method is selected to build the microstructure evolution model in thispaper.In order to establish the microstructure evolution model of7050aluminum alloy inthermoplastic deformation, the following work have been done in this paper. First, hotcompression experiments are carried on used Gleeble1500thermal simulation machine,the true stress-strain curves under different temperature and strain rate are obtained. Therheological behavior and microstructure evolution rule under different deformationconditions of7050aluminum alloy are analyzed qualitatively. The softening mechanismof7050aluminum alloy in the case of high temperature and low strain rate is mainlydynamic recrystallization. The flow stress equations are built which can describe therelationship bettween flow stress and temperature and strain rate; Second, based on theMATLAB software, according to the curvature-driven mechanism of grain growth andthe conditions of grain boundaries maintaining stability, the grain growth cellularautomata model of a single phase grain is established. Combined with the actual compression process, topology model of grain deformation is established, so that thesimulation can in accordance with the actual situation; Finally, the transformation ofdislocation is the essence of the metal plastic deformation, the cellular automata modelof dynamic recrystallization process is established based on dislocation-drivenrecrystallization nucleation mechanisms and the kinetic theory of grain growth. Then,simulating the hot compression process under different conditions used this model,analyzing the effects of strain, deformation temperature and strain rate on dynamicrecrystallization behavior, comparing with the thermal compression experiments. Theresults of simulation are in accordance with the experiment results and theory. Therationality the dynamic recrystallization CA model in this paper is proved.