Researchon Microstructure Evolution Andinter-granularcorrosionbehaviorof 6082 Aluminumalloy

6000 series aluminum alloys generally have no inclination of inter-granular corrosion,but adding Cu to alloy,mass ratio of Mg and Si is inappropriate or improper heat treatment process will reduce the inter-granular corrosion resistance property of 6000 series aluminum alloys.In this paper,based on the 6082 extrusion and forging aluminumalloyas theresearch material,bytheanalysismeans of optical microscope(OM),scanning electron microscope(SEM),and its own energy dispersive spectrometer(EDS),backscattered electron diffraction(EBSD),transmission electron microscope(TEM)and vickers hardness tester,adopted the test means of inter-granular corrosion experiments and vickers hardness measurement,analyzed and studied the microstructure evolutionand inter-granular corrosion behavior of 6082 aluminum alloy,theresults show that:For 6082-T6 aluminum alloy,as the extension of inter-granular corrosion time,the maximum corrosion depth increases gradually,when the corrosion time is more than 5 h,increased amplitude of longitudinal maximum corrosion depth is small,but the corrosionat the grain boundary extends to intracrystallineis more and more serious,the horizontal scope of corrosion and corrosion degree increasegradually.For 6082-T6 aluminum alloy,the homogenization temperature increases from 510 ?to 530 ?,homogenization processing timeextends from6 h to 8 h,recrystallization grain size is more small,composition organization is more uniform,the maximum inter-granular corrosion depth reduces,and the higher homogenization temperature make maximum inter-granular corrosion depth reducemorethan the extension of the homogenization time,this shows that homogenization treatment temperature influences the alloy inter-granular corrosion resistanceproperty more significantly than the processing time.After inter-granular corrosion,for 6082-T6 aluminum alloy forgings,in the middleareaoccurheavycorrosionandinthesurrounding areaoccur light corrosion phenomenon,light corrosion area is single crystal organization,is a very coarse grain;heavy corrosion area is polycrystalline organization,this area not exists in segregation of solute atoms and no precipitationon grain boundary,explain that the reason of the heavy corrosion has nothing to do with the grain boundary precipitates.The non-uniform deformation is caused byextrusion process and forging process is the main reasonfor the coarse grain structure after solid solution treatment of the forging,non-uniform deformation can make the alloy grain boundary interface energy increase,crystal nucleus growrapidly,and to form a coarse grain structure.For 6082 aluminum alloy used in this paper,atom partial phenomenon does not occur and has no precipitated phaseon the grain boundary,the reasons of inter-granular corrosion has nothing to do with grain boundary precipitates,inter-granular corrosion is caused by point corrosion leading to the surrounding matrix gradually dissolve and extending to the grain boundary,the point corrosion is caused by the potential difference between ?-Al matrix and Mg2 Si phase andthe potentialdifference between ?-Al matrixSi particle,pitting corrosionprocess includesthe germination and the extensionof pitting corrosion,pittingcorrosion first occurs in the intracrystalline or near grain boundary,combining to the electrochemical reaction,analyze the mechanismofpitting corrosion of 6082 aluminum alloy.