摘要
在空冷与强制冷却下对2198-T3/7A04-T6异种铝合金进行搅拌摩擦拼焊,并在焊后对其接头进行低温时效处理,研究了强制冷却和低温时效对焊接接头低硬度区微观组织特征及接头力学性能的影响。研究发现,两种条件下,2198-T3铝合金一侧的热影响区内均出现了低硬度区,但强制冷却+低温时效条件下接头低硬度区的硬度值明显更高,为94.5 HV0.1,并且接头的平均屈服强度、抗拉强度和伸长率分别为312 MPa、443 MPa和8.9%,屈服强度和抗拉强度分别达到母材强度的97.5%和96.9%,而空冷+低温时效条件下仅为母材强度的89.0%和91.6%。强制冷却+低温时效条件下接头的力学性能更优的主要原因是:焊接过程中施加强制冷却能有效抑制接头低硬度区内θ′相T1相的溶解与粗化,使其在后续低温时效过程中能获得更好的时效强化效果。
2198-T3/7A04-T6 dissimilar aluminum alloy was friction stir welded under air cooling and forced cooling respectively,and the joint was aged at low temperature after welding.The effects of forced cooling and low temperature aging on the microstructure characteristics and mechanical properties of the welded joint were studied.It's found that a low hardness zone appears in the heat affected zone of the 2198-T3 aluminum alloy side under both conditions,but the hardness value of the low hardness zone of the joint under forced cooling+low temperature aging conditions is significantly higher,reaching 94.5 HV0.1.The average yield strength,tensile strength and elongation of the joint are 312 MPa,443 MPa,and 8.9%,respectively.The yield strength and tensile strength reach 97.5% and 96.9% of the base material strength,respectively.However,under air cooling and low temperature aging conditions,they are only 89.0% and 91.6% of the base material strength.The main reason for the better mechanical properties of joint under forced cooling and low-temperature aging conditions is that applying forced cooling during the welding can effectively suppress the dissolution and coarsening of θ′ and T1 phases in the low hardness zone of the joint,enabling it to achieve better aging strengthening effect in the subsequent low-temperature aging treatment.
作者
孙博
聂佳民
李晓丹
何长树
Sun Bo;Nie Jiamin;Li Xiaodan;He Changshu(School of Materials Science and Engineering,Northeast University,Shenyang Liaoning 110819,China;Key Laboratory of Anisotropy and Texture of Materials,Northeast University,Shenyang Liaoning 110819,China;Shenyang Aircraft Industry Group Co.,Ltd.,Shenyang Liaoning 110850,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2023年第9期8-13,共6页
Heat Treatment of Metals
关键词
低温时效
水下搅拌摩擦焊
析出相
力学性能
low temperature aging
underwater friction stir welding
precipitated phase
mechanical properties
