The Effects Of Texture Evolution On Mechanical Properties Of Al/Mg/Al Clad Sheets During Rolling And Annealing

Magnesium and magnesium alloys are the lightest structural materials in the word now.They are widely used for their high specific intensity?excellent electromagnetic shielding property and vibration reducing performance,but their poor corrosion resistance limits their application.However,aluminum alloy has good plasticity and good corrosion resistance.Therefore,the surface of magnesium alloy covered with layers of aluminum alloy sheets can not only play the advantages of magnesium alloys but also prevent magnesium alloy from being corroded.Here,5052 aluminum alloy sheets were coated on both sides of AZ31 magnesium alloy sheets,and then they were rolled into one.5052/AZ31/5052 magnesium-aluminum clad sheets were prepared by rolling at different rolling speed and reduction.Then magnesium-aluminum clad sheets with good property were annealed at different temperature and time.The influence of rolling speed and reduction,annealing temperature and time upon the microstructure evolution,texture evolution and tensile properties of rolled 5052/AZ31/5052 clad sheets was investigated.Magnesium-aluminum clad sheets were rolled at the speed of 6.12m/min and different rolling reduction,33% and 40% reduction could obtain a good surface state of Al/Mg/Al clad sheets,and the surface of clad sheets cracked when the rolling reduction was 48%.When the rolling reduction was increased,the shear band of magnesium layer became wide,the basal texture increased significantly,LAGBs?dislocation density and volume increased,the increase of DRX leaded to the increase of fine grains.With the increase of rolling reduction,the amount of slip systems increased,grains refinement for aluminum layers,the dislocation increased,the S?C?B texture arose,S texture was stronger,and the C and B textures were strengthened when rolling reduction increased.The tensile strength of Al/Mg/Al clad sheets increased while the ductility decreased.The surface state of Al/Mg/Al clad sheets when the rolling reduction was 40% at different rolling speeds.With the increase of rolling speed,the shear band of magnesium layer became thin and short gradually,the increasing of DRX leaded to the increase of fine grains,the basal texture strength decreased,non-basal slip system was activated at the same time,dislocation increased.The grain size of aluminum layers was finer when the rolling speed increased.And there were S,C,B texture at different rates,the S type texture was the strongest,the texture strength decreased,and the texture of B and C was strengthened.The tensile strength and elongation were no difference,the tensile strength decreased and the plasticity increased when the rolling speed increased.Al/Mg/Al clad sheets occurred SRX when they were annealed at 200??300? and 400? for 1hour.While two obvious intermetallic layers Al3Mg2 and Mg17Al12 formed after annealing at 300? and 400?.The higher temperature,the thicker intermetallic layers.With the increase of annealing temperature,the recrystallization degree of magnesium layer increased,and the complete recrystallization occurred above 300?.The basal texture was reduced gradually,the grain size decreased and then increased,the dislocation disappeared gradually.The aluminum layers had not occurred recrystallization at 200?,partial recrystallization at 300?,400? then fully recrystallized.With the increase of annealing temperature,S?B?C texture weakened gradually and disappeared at 400? and then they became cubic texture and a small amount of R texture.The strength and plasticity increased with the increase of annealing temperature and then decreased.Al/Mg/Al clad sheets were annealed at 300? for 0.5h?2h?5h.Mg layer and Al layers had undergone recrystallization above 300?,the degree of recrystallization increased and Mg layer happened complete recrystallization when the annealing time reached 1h,Al layers occurred complete recrystallization for 2h.The basal texture intensity decreased,dislocations reduced.At first,the grain size decreased and then increased.The grains of Mg layer appeared 86°{101?2} tensile twins when the annealing rose to 5h.With the increase of annealing time,the S?B and C textures disappeared gradually,then the cubic texture and a small amount of R texture were formed.The tensile strength and plasticity increased first and then decreased when the annealing time increased.The strength and ductility were best when the Al/Mg/Al clad sheets were annealing at 300?for 2h,it indicated that 2h-300? is the best parameter of 5052/AZ31/5052 clad sheets for annealing.