Effect Of Heat Treating On Microstructure,Properties And Surface Morphology Of 2a12 Aluminum Alloy Thin Sheet Cladded With Pure Aluminum

2A12 aluminum alloy clad aluminum sheet is widely used in aircraft skin due to its excellent performance.In this paper,the effects of annealing,solution treatment and post-anneal solution heat treatment on the structure,properties and surface morphology of 2A12 aluminum alloy clad aluminum sheet were studied using OM,SEM,EBSD,room temperature tensile properties test and surface morphology test analysis methods The rules obtained the following experimental results and conclusions.The effect of annealing heat treatment on the microstructure and properties and surface morphology of alloy materials was studied.After annealing and heat treatment at 380℃/2.5 h,the alloy plate has lower strength and higher elongation,the matrix structure of the plate has obviously recovered,and the grain diameter is relatively large.After annealing,the surface of the plate after 16%pre-stretch deformation showed a blocky orange peel.The roughness of the surface of the plate gradually decreased with the increase of annealing temperature and the extension of the holding time.The effects of solution heat treatment and natural aging after solution on the structure and morphology of alloy sheet were studied.The alloy matrix after solution treatment is mainly a fine recrystallized grain structure.With the increase of the solution temperature,the grains tend to increase.The phases in the matrix gradually dissolve back with the increase of temperature and the extension of the holding time.The remaining phases Most of them are insoluble Fe-rich phases.The plate after 495℃/10 min and 96 h natural aging treatment has better tensile properties.After 96 hours of natural aging,the properties and morphology of the alloy did not change significantly.After solution treatment,the surface of the plate after 16%pre-stretch deformation exhibits a small dense block shape.As the amount of deformation increases,the surface appearance of the plate changes from the slip line organization to the adjacent slip line to the final complete Blocky orange peel.The effect of solution heat preservation time after annealing on the microstructure properties and surface morphology of the alloy was studied,compared with the alloy which was directly solution treated.The grain size of the matrix after solution treatment is relatively large and the strength is reduced by 5-7%after annealing.With the extension of the solution retention time after annealing,the tendency of the surface roughness of the plate to increase is not obvious.By comprehensively comparing the effects of various heat treatment schemes on the structure and surface morphology of the alloy sheet,it is found that the solution heat treatment of the cold-rolled 2A12 aluminum alloy clad aluminum sheet directly at 495℃/10 min is high,and better performance and surface can be obtained.