Hot Plastic Deformation Behaviors And Numerical Simulation Of GW93 Magnesium Alloy

Magnesium alloys are the lightest metal structure material, they are widely used in many fields. Microstructure, mechanical properties and corrosion resistance could be improved obviously by alloying with rare-earth elements of gadolinium and yttrium in the magnesium alloys. Therefore, more and more attentions are attracted to the Mg-Gd-Y alloys in recent years. Structure and properties of the metal materials could be improved well by hot plastic deformation, especially for magnesium alloys. The grains are refined, the capability of plastic is increased, and the mechanical properties are improved by the process of dynamic recrystallization in hot plastic deformation.There are a lot of complex problems in plastic deformation process of metal material, for exampe, the law of plastic deformation, the influence of different deformation conditions on the microstructure and mechanical properties, the phenomenon of dynamic recrystallization, the friction between mould and material, and so on. People lack accurate analysis method in plastic deformation process of metal, just depend on experience of researchers is not enough. The stress, the law of deformation, the microstructure evolution, and the potential defects etc., which could be forecasted by numerical simulation in metal plastic deformation process. There is very helpful to experimental research and actual production.The hot plastic deformation behaviors and the law of microstructure evolution of GW93 magnesium alloy are researched by using hot compress test and numerical simulation. The true stress-ture strain curves of GW93 magnesium alloy are drawn by the data of hot compress test in a wide range of temperatures (653-753K) and strain rates (10-2-10s-1). The influence of different deformation conditions in hot compressive deformation behaviors is researched. Results show that, the stress level and the peak flow stress decrease with the deformation temperature increases, and increase with the strain rate increases. The constitutive model is established, which can describe the flow stress in different strain accurately, and provide a reliable basis for numerical simulation of hot compressive deformation behaviors. The numerical simulation platform for the hot plastic deformation behaviors of GW93 magnesium alloy is established by using DEFORM-3D finite element software, and the hot compressive deformation behaviors is simulated. The results of numerical simulation consistent with the results of experimental. The equation in the constitutive is:The microstructure of the compressive GW93 magnesium alloy is observed. The microstructure evolution is simulated by using cellular automata method and dynamic recrystallization model. The influence of different deformation conditions in dynamic recrystallization is researched. The results of numerical simulation consistent with the results of metal lographic observation. Results show that, there is obvious nonuniformity in hot compressive deformation of cylindrical sample. The degree of dynamic recrystallization and the grain size increase with the deformation temperature increases, and decrease with the strain rate increases.