Study On The Effect Of Heat Treatment On The Microstructures And Properties Of 5052 Aluminum Alloy With Friction Stir Processing And Rolling Deformation

After the material is processed by friction stir,fine equiaxed crystal structure can be obtained.However,due to the difference of temperature field and strain field at different locations in the processing area,the processing structure is not uniform.This results in the abnormal growth of grains in the processing area under certain conditions,resulting in the change of material properties and loss of superplasticity.Therefore,the application of friction stir processing technology in the field of material superplasticity is greatly limited.At present,there is a lack of systematic study on the microstructure characteristics and grain abnormal growth of aluminum alloy 5052 before and after heat treatment,and there are only few studies on the influence of deformation on the microstructure of aluminum alloy processing area before and after heat treatment.This article 6 mm thick 5052 aluminum alloy was used for friction stir processing(abbreviated as FSPed),under different processing parameters(advance speed is 80mm/min,stirring speed is 400 rpm,800 rpm,1200 rpm,respectively).The processing structure of the 400 FSPedand 1200FSPed sample were deformed by 10% and 30%respectively(abbreviated as 400FSPed-10%?1200FSPed-10%?400FSPed-30%?1200FSPed-30%).Through the heat treatment of friction stir processing and its deformed tissue under different conditions,the abnormal grain growth rule and influencing factors of aluminum alloy 5052 aluminum alloy friction stir processing after heat treatment were systematically studied,as well as the influence of deformation on the processed tissue before and after heat treatment.The conclusion are as follows:Under different friction stir processing parameters,the larger the heat input,the larger the grain size in the welding core.For each processing parameter,the grain size in the core zone from large to small: stirring zone > axial shoulder influence zone > vortex zone.The texture in processing area are mainly //(?) and type shear texture.The effect of processing parameters on abnormal grain growth in the processing area is as follows: Abnormal grain grew up under different processing parameters of intensity is 400FSPed>800FSPed>1200FSPed.The abnormal growth sequence of grains in the processing area was as follows: axial shoulder influence zone,vortex zone,forward side heat engine influence zone,backward side heat engine influence zone,and stirring zone.After the friction stir processing area is deformed,the larger the deformation is,the wider the original welding core area is,and the more obvious the grain refinement of the processing structure is.Friction stir processing areas after 10% deformation and heat treatment,1200 FSPed sample grain coarsening to millimeter,coarsening more severe than without deformation;After 30% deformation and heat treatment,the grains of the400 FSPed and 1200 FSPed samples did not grow abnormally,but recrystallized dynamically and grew normally at a slower rate.Sample without heat treatment,the elongation of tensile sample order from large to small is 1200 PSPed ?800FSPed?400FSPed?1200FSPed-30%?400FSPed-30%,the average hardness law of the core area of the samples is contrary.Samples in 470 ?heat preservation after 2h and heat treatment,the tensile elongation from big to small is400FSPed>1200FSPed-30%>1200FSPed>400FSPed-30%,The average rule of the core area sample is contrary.