Influence of di fferent size tunnel defects on mechanical properties of FWS jointsFull text replacement

不同尺寸隧道缺陷对FSW接头力学性能的影响全文替换 Influence of di fferent size tunnel defects on mechanical properties of FWS jointsFull text replacement 刘洋 Full text replacementLIU Yang 1 first-author 许鸿吉 XU Hongji 1 大连交通大学研究生院 大连交通大学研究生院 Graduate School, Dalian Jiaotong University Graduate School, Dalian Jiaotong University 对6005A-T6中空铝型材进行工艺试验制备隧道缺陷,进行金相、硬度、拉伸试验,拉伸后扫描断口,研究不同尺寸缺陷对6005A-T6中空铝型材力学性能及微观组织的影响。试验结果表明:接头抗拉强度与板厚方向隧道尺寸呈负相关,SEM扫描结果显示拉伸断口中心及边缘存在大量等轴韧窝,均为韧性断裂;隧道缺陷均位于前进侧焊核靠下部分,焊核区及隧道附近受到强烈的机械搅拌作用,发生了动态再结晶过程,均为细小的等轴晶。热影响区组织与母材相差不大,两个区域均在型材轧制方向晶粒被拉长;在前进侧及后退侧均存在软化区,后退侧由于热-机作用硬度值最低为63.6 HV,前进侧硬度最小值为84 HV。 The tunnel defects were prepared through process tests on 6005A-T6 hollow aluminum profiles, and metallographic,hardness and tensile tests were carried out. After stretching, the fracture was scanned to study the effects of different size defects on the mechanical properties and microstructure of 6005A-T6 hollow aluminum profiles. The test results show that the tensile strength of the joint is negatively correlated with the tunnel size in the thickness direction. The SEM scan results show that there are a large number of equiaxed dimples at the center and edge of the tensile fracture, all of which are ductile fractures; the tunnel defects are all located in the lower part of the weld nugget on the forward side, the weld nugget zone and the vicinity of the tunnel are subjected to strong mechanical stirring, and a dynamic recrystallization process occurs, all of which are fine equiaxed crystals. The microstructure of the heat-affected zone is not much different from that of the base metal, and the grains in these two zones are elongated in the rolling direction of the profile; there are softening zones on the forward and backward sides, and due to heat-mechanical action, the minimum hardness value of the backward side is 63.6 HV, the minimum hardness value of the forward side is 84 HV. 搅拌摩擦焊 6005A铝合金 隧道缺陷 组织与力学性能 friction stir welding 6005A aluminum alloy tunnel microstructure and mechanical properties U451;TG407 2022-03-08 9 51