摘要: |
对20mm厚7050-T7451铝合金进行搅拌摩擦焊和接头的焊后热处理。对比分析了热处理前后接头的组织和性能。结果表明:在搅拌头旋转速度300r/min,焊接速度50mm/min时,接头抗拉强度为426MPa,延伸率为8.2%。经过固溶时效处理后,接头组织细化,并析出大量第二相粒子,接头性能进一步提高,抗拉强度达到511MPa,延伸率为8.5%;热处理前接头均断裂于前进侧热影响区,与接头的硬度分布有对应关系。热处理后,接头断裂于焊核区。热处理前后接头断口均表现出韧性断裂特征。 |
关键词: 搅拌摩擦焊;热处理;微观组织;力学性能 |
基金项目: |
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Effects of Post-weld Heat Treatment on Friction Stir Welding Joints of 7050 Aluminum Alloy |
Zhang Xin Han Dong Wu Jun Yin Kai
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Xi’an Aerospace Power Machine Factory, Xi’an 710025
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Abstract: |
The microstructure and property before and after heat treatment of friction stir welded 20mm 7050 aluminum alloy were investigated.The results show that when the tool rotating speed is 300r/min and the welding speed is 50mm/min, the tensile strength can reach 426MPa and the elongation is 8.2%, which are regarded as the most ideal parameters under experimental conditions.After heat treatment, the microstructure of joint was refined and a large number of second phase particles precipitated, the tensile strength can reach 511 MPa.Before heat treatment, the lowest hardness appears in thermomechanically affected zone (TMAZ) of advancing side, and the fracture path appears in this area. After heat treatment, the fracture path appears in nugget zone (NZ). The fractography has a characteristic of dimples of strengthening phase. |
Key words: friction stir welding;heat treatment;microstructure;mechanical property |