Fe和Si杂质元素对7×××系高强航空铝合金组织及性能的影响

摘要

Effects of Fe and Si impurities on the microstructure and mechanical properties of 7××× series aircraft aluminum alloys are overviewed.The Fe and Si impurities mainly form coarse and insoluble intermetallic particles in the microstructure.Among a variety of iron rich intermetallics,Al7 Cu2 Fe phase is typically found in the alloys with higher Cu content while the Mg2 Si phase is the main silicon rich intermetallics.The increase of the Fe and Si contents has little effect on the strength,but markedly reduces the plasticity,fracture toughness and stress corrosion resistance of 7××× aluminum alloys in that the contents of coarse Fe-rich and Si-rich insoluble impurity phases increases.Reducing the contents of Fe and Si impurities is significant to develop the high comprehensive properties of aircraft aluminum alloys.%综述了Fe、Si杂质元素对7×××系高强航空铝合金的微观组织及力学性能的影响.Fe、Si主要是以粗大难溶杂质相形式存在.形成含Fe杂质相的种类较多,在含Cu量较高的合金中主要是形成Al7Cu2Fe相；形成含Si杂质相主要是Mg2 Si相.Fe、Si杂质元素含量增加对合金强度的影响不大,但形成的富Fe、富Si粗大难溶杂质相含量的增加明显降低合金的塑性、断裂韧性和抗应力腐蚀性能.降低Fe、Si杂质元素含量是发展高综合性能航空铝合金的重要方向.