时效处理对6061铝合金MIG焊接头组织和性能的影响

摘要

The solution and aging treatments of MIG weld joint for 6061 aluminum alloy are conducted with the solution temperature of 530 ℃ and heat preservation of 4 hours,and aging temperature of 140 ℃,160 ℃,180 ℃ and 200 ℃ respectively and heat preservation of 6 hours.The effect of aging temperature on the microstructure,mechanical properties and fracture mechanism of the welded joint is analyzed.Experimental results show that the postweld solution and aging treatments can effectively improve the softening and mechanical properties of welded joint.The metallographic structure of welds is mainly α(A1) + β(Mg2Si),and the distribution is uniform.The distribution of enhance phase β (Mg2Si) is dispersed,which plays a role of dispersion strengthening,and a better comprehensive mechanical property can be obtained when the aging temperature is 180 ℃ with heat preservation of 6 hours.%选取固溶温度530℃,保温时间4h,时效温度分别为140℃、160℃、180℃、200℃,保温时间6h,对6061铝合金MIG焊接接头进行固溶时效处理.分析时效温度对接头组织、性能和断裂机理的影响.结果表明:焊后固溶时效处理能有效改善接头软化现象,提高力学性能;焊缝的金相组织主要为α(Al)+β(Mg2Si),且分布较均匀,强化相β(Mg2Si)的分布较为分散,起到了弥散强化作用;时效温度180℃、时间6h时可获得综合力学性能较好的接头.