Effects Of Fe Element And Heat Treatment Process On Microstructure And Properties Of 6082 Aluminum Alloy

In this paper,two kinds of rolled 6082 aluminum alloys with different Fe content were studied.By means of metallographic microscopy,scanning electron microscopy,transmission electron microscopy,hardness test and tensile test at room temperature,the effects of alloying elements Fe,single-stage solid solution and double-stage solid solution on the structure,properties and quenching sensitivity of6082 aluminum alloy rolled sheet were studied in order to improve the strength of the alloy and reduce the quenching sensitivity of the alloy.The results are as follows:Fe element mainly exists in Al_0.7Fe₃Si_0.3 phase in 6XXX aluminum alloy.The increase of Fe element will result in the coarse structure of 6082 aluminum alloy after solution quenching treatment,at the same time,it has a significant effect on the supersaturation of the matrix.With the increase of Fe content,the content of Mg₂Si phase with high melting point in the matrix decreases,and the quenching sensitivity of the alloy increases,which increases by 3.23%when characterized by tensile strength.It can be found that with the increase of Fe content,there will be more Fe-rich phase particles.This is one of the reasons why the quenching sensitivity of 6082aluminum alloy with 0.35%Fe content is higher than that of 6082 aluminum alloy with 0.15%Fe content.When the Fe content is 0.35%,the degree of solution of 6082 aluminum alloy increases with the increase of solution temperature.When the solution temperature is higher than 540?,the increase of temperature has little effect on increasing the degree of supersaturation of solid solution.When the solution temperature reaches555?,the 6082 aluminum alloy is overburned.The higher the solution temperature is,the greater the strength of the alloy is.After solution treatment at 545?and aging at 170?for 8 h,the tensile strength of the alloy reaches 350 MPa.When Fe content is 0.15%,after solid solution treatment of 6082 aluminum alloy,there are still a large number of high-solubility iron-rich phase particles which do not dissolve into the matrix.The optimal two-stage solid solution process of 6082aluminum alloy is 515?/30 min+545?/30 min,which has the best effect on restraining recrystallization and the highest degree of supersaturation after quenching.