Study On Microstructure Evolution And Technology Of Compound Deformation Of Magnesium Alloy Sheet

Magnesium alloy is one of the most important light metal materials,and it has a wide range of applications in the exploration of automobile,aerospace and outer space.Because magnesium alloy crystal structure belongs to the hexagonal close-packed crystal structure,it has poor plastic deformation ability at room temperature.So,improvement of magnesium alloy properties is an important research direction.In this paper,the numerical simulation method is used to analyze the compound deformation process of AZ31 magnesium alloy.Law of microstructure evolution is researched by cellular automaton during compound deformation.Texture distribution is analyzed by EBSD experimental method.The following research work has been completed and the relevant conclusions have been obtained.(1)DEFORM software is used to simulate indentation and flattening pro cess of AZ31.The distribution of temperature field,stress field,dynamic recrys tallization fraction and grain size are analyzed.And the influence rule of defor mation temperature,tooth spacing and reduction on the compound deformation of magnesium alloy is obtained.(2)The cellular automaton method is used to study the microstructure e volution during the process of combined deformation.The influence of deforma tion temperature,spacing and reduction on dynamic recrystallization and grain size during the process of composite deformation is obtained.(3)Tools of indentation and flatting compound deformation are developed,and the experimental study on the compound deformation of AZ31 magnesium alloy is carried out.The results of the experiment proved that the die structure is reasonable.The experimental results show that the grain in the central deformation zone is finer than that in the edge deformation zone,and the deformation temperature is 300 ℃-350℃.(4)The texture distribution of compound deformation of magnesium alloy is analyzed by EBSD.The texture of magnesium alloy is weakened in crystal surface{0001},{10 1 0} and {112 0} during compound deformation.The texture strength of magnesium alloy in crystal surface {0001} is 6.49,reduced about 60%.In crystal surface {10 1 0} and {1120},the texture strength is 3.28,3.46,respectively.(5)Through comprehensive analysis of the above results,the parameters of compound deformation process are that the deformation temperature is 300℃,the reduction is 3mm,tooth spacing is 10mm.Magnesium alloy sheet occ urs full dynamic recrystallization,the grain is refined and texture is weakened.