Fe含量对7075铝合金的显微组织与性能影响

Effects of Fe Content on Microstructure and Properties of 7075 Aluminum Alloy

通过铸锭冶金制备了不同Fe含量的7075铝合金,并对其进行了均匀化热处理、热挤压处理及固溶时效处理。采用金相显微镜、扫描电镜、透射电镜、拉伸性能及腐蚀性能测试,研究了Fe含量对7075铝合金显微组织与性能的影响。结果显示,基体合金中添加Fe元素后,显微组织主要由α-Al基体相、T相、S相、Al_(7)Cu_(2)Fe、Al3Fe等相组成,且热处理不会对富Fe相有明显影响。随着Fe含量增加,合金的抗拉强度先减小后略有升高,均为540 MPa左右,伸长率逐渐减小,且Fe含量增加到0.3%时,合金的抗腐蚀性能急剧下降。当w(Fe)<0.3%时,合金综合性能无显著下降。

7075 aluminum alloys with different Fe contents were prepared by ingot metallurgy, and subjected to homogenization heat treatment, hot extrusion treatment, and solution aging treatment. Effects of Fe addition on microstructure and mechanical properties of 7075 aluminum alloy were investigated by metallographic microscope, scanning electron microscope, transmission electron microscope, tensile property, and corrosion property tests. The results indicate that the microstructure mainly consists of α-Al matrix phase, T phase, S phase, Al_(7)Cu_(2)Fe, Al_3Fe, and other phases after adding Fe, and heat treatment has little impact on Fe-rich phase. As Fe content increases, the tensile strength of alloy is firstly decreased and then increased slightly, reaching about 540 MPa. The elongation is gradually decreased and the corrosion resistance is decreased sharply with Fe content increasing to 0.3%. In summary, with w(Fe) less than 0.3%, the overall performance of the alloy has no significant reduction.