Effects Of Hot Extrusion And Rolling Process On Microstructure And Properties Of AE44 Magnesium Alloy

Magnesium alloys have the advantages of light weight,high specific strength and high specific rigidity.As a new generation of lightweight metal structural materials are widely used in automotive,aerospace,aerospace,3C products and home appliances and other industries.At present,magnesium alloy products are mainly obtained by casting.If the magnesium alloy is subjected to deformation such as extrusion and rolling,its performance will be greatly improved.This paper takes AE44 magnesium alloy as the research object,discusses the influence of different hot extrusion and rolling process parameters on the microstructure and properties of AE44 magnesium alloy,seeks optimized extrusion and rolling process parameters,and formulates suitable deformation processing for actual production.The process provides the theoretical basis.In this paper,metallographic microscope,X-ray diffractometer,scanning electron microscope,Brinell hardness tester,tensile tester and other experimental instruments were used to analyze the microstructures of AE44 magnesium alloys under different hot extrusion temperatures,extrusion speeds and different rolling deformations.The effect of mechanical properties.The results of the study are as follows:(1)After AE44 magnesium alloy was deformed by hot extrusion,the microstructure of the alloy was dynamically recrystallized,the matrix was transformed from dendritic to equiaxed crystals,and the precipitated phase was streamlined.In the experimental temperature range,with the increase of extrusion temperature,the grain size first decreases and then increases.At 340℃,the size is the smallest,which is 13.86 μm.The best mechanical properties were also obtained at 340℃.The yield strength,tensile strength and elongation at room temperature were 180.7MPa,265.2MPa and 9.5%,respectively.The tensile test was performed at 150℃ and 200℃,and the yield strength and tensile strength were 122MPa,101 MPa and 164MPa,129MPa,respectively.The elongations were 20.85%and 24.97%,respectively,and they were ductile and brittle fractures at room temperature,150℃.And tensile elongation at 200℃ is a tough fracture.(2)The hot extrusion speed has a certain influence on the microstructure and mechanical properties of AE44 magnesium alloy.When the extrusion temperature is 400℃,the grain size of the alloy first decreases and then increases with the extrusion speed ranging from 1 mm/s to 2 mm/s to 3 mm/s.The yield strength,tensile strength,elongation and hardness of the alloy all increased first and then decreased.The maximum values were reached at an extrusion speed of 2 mm/s,which were 191.2 MPa,259.2 MPa,7.2%,and 62 HB,respectively.(3)The as-cast AE44 magnesium alloy is heated to 400℃ and rolled for 30 minutes per pass.The maximum deformation can reach 80%.When the cumulative rolling deformation is 30%,50%,70%,and 80%,respectively,the grain size decreases,and the yield strength and tensile strength of the alloy successively increase.The maximum values are 197.3 MPa and 259.3 MPa,respectively..The elongation rate increases first and then decreases,reaching a peak value of 7.8%when the deformation amount is 70%.(4)After the sheet was annealed at 250℃ for 1 h,the static recrystallization was complete,the average grain size was 14.34 分μm,and the yield strength,tensile strength,elongation after elongation,and hardness were respectively 179.1MPa,258MPa,and 10.3%.And 60.6HB.(5)Analysis of the microstructure and mechanical properties of the composite AE44 magnesium alloy.Within the experimental parameters,the optimized extrusion and rolling process parameters are:extrusion temperature 340℃;extrusion speed 2 mm/s;rolling deformation 80%;annealing process parameters after 250 ℃ x1h.