LY12铝合金搅拌摩擦焊接头组织和性能研究
Study on Microstructure and Mechanical Properties of Friction Stir Welded Joint of LY12 Aluminum Alloy
刘鸽平， 杨成刚， 柯黎明
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作者单位：南昌航空大学 航空制造工程学院，江西 南昌330063
中文关键字：搅拌摩擦焊； 接头强度； 微观组织
英文关键字：friction stir welding； joint strength； microstructure
中文摘要：研究了搅拌头旋转速度n与焊接速度v之比即n/v比值大小对LY12铝合金搅拌摩擦焊接头组织和力学性能的影响。结果表明，n/v比值较小时，焊接线能量较小，接头存在孔洞缺陷，严重降低了接头力学性能；随着n/v比值逐渐增大，孔洞缺陷尺寸逐渐减小；当n/v比值为5时，焊接线能量适当，接头无缺陷，焊核区为细小均匀的等轴晶，因此接头强度最高，达427 MPa；当n/v比值继续增大，焊核区晶粒组织也随之粗化，接头强度逐渐降低。
英文摘要：The effects of the ratio of rotation speed of weld tool(n) and weld speed (v) on microstructure and mechanical properties of the welded joint of LY12 aluminum alloy were investigated. The results show that when the value of n/v was little, the welding heat input is also insufficient, so there are hole defects in joint, which severely decreases the strength of the joint. With the value of n/v increasing, the size of the hole defects reduces. When the n/v value is five, the optimum heat input could be obtained, there is not defect in joint, the microstructure of the weld nugget is almost fine equiaxed grains, the joint strength is highest, which is 427 MPa. With the continuous increase of n/v value, the grains in weld nugget are coarse, so the joint strength decreases.