Fe含量对2219铝合金锻件焊接组织与性能的影响

为研究杂质Fe元素对2219铝合金及其焊接接头的组织、性能以及电化学腐蚀性能等的影响,采用力学拉伸、焊接试验以及金相和扫描电镜等分析测试方法,对0.15%(w)至0.01%(w)等不同Fe元素含量的2219铝合金锻件进行实验研究和分析。研究表明:2219铝合金中经热变形加工存在网络状Al_2Cu变成颗粒状和纤维状的Al_7Cu_2(Fe,Mn)相,随着Fe含量由0.15%(w)降低至0.01%(w),合金固溶时效后的Al_7Cu_2(Fe,Mn)相显著减少,锻件强度和塑性显著提高;合金焊接接头断口由脆性断裂逐渐转变为韧窝尺寸细小的韧性断裂,尤其对于延伸率,提高至近1.4倍,强度和塑性显著提高;合金的自腐蚀电流逐渐减小,单位面积上的线性极化电阻增大,合金焊接接头的耐腐蚀性能显著提高。

Effect of Fe Content on Welding Microstructure and Properties of 2219 Aluminum Alloy

In order to study the influence of Fe content on the microstructure,properties and electrochemical corrosion properties of 2219 aluminum alloy and its welded joints,mechanical tensile test,welding test, metallographic and scanning electron microscope were used to conduct experimental research and analysis on 2219 aluminum alloy forgings with different Fe contents from 0.15%(w) to 0.01%(w).The results show that there are Al₇Cu₂(Fe,Mn) phases in 2219 aluminum alloy which are transformed into granular and fibrous Al₇Cu₂(Fe,Mn) phase after thermal deformation processing.With the decrease of Fe content from 0.15%(w) to 0.01%(w),the Al₇Cu₂(Fe,Mn) phase after solid solution aging of the alloy is significantly reduced, and the strength and plasticity of the forging are significantly increased.The fracture of the alloy welded joint is transformed from brittle fracture to ductile fracture with small dimple size.The strength and plasticity are significantly increased,and elongation is increased to nearly 1.4 times especially.The corrosion current of the alloy decreases gradually and the linear polarization resistance per unit area increases,so the corrosion resistance of alloy welded joints is improved significantly.