大断面6082铝合金型材FSW接头的“S”线特征及其对分层力学性能的影响  

Characteristics of"s"line of FSW joint of large section 6082 aluminum alloy profile and its influence on delamination mechanical properties

作　　者：张风东 张成国 邢艳双 王振宇 李颖 刘思奇 何长树 ZHANG Feng-dong;ZHANG Cheng-guo;XING Yan-shuang;WANG Zhen-yu;LI Ying;LIU Si-qi;HE Chang-shu(CRRC Qingdao Sifang Locomotive Vehicle Co.,Ltd.,Qingdao 266111,China;China Academy of Railway Sciences Co.,Ltd.,Beijing 100081,China;School of Materials Science and Engineering,Northeastern University,Shenvang 110819.China;Key Laboratory for Anisotropy and Texture of Materials,Northeastern University,Shenyang 110819,China)

机构地区：[1]中车青岛四方机车车辆股份有限公司,山东青岛266111 [2]中国铁道科学研究院集团有限公司机车车辆研究所,北京100081 [3]东北大学材料科学与工程学院,辽宁沈阳110819 [4]东北大学材料各向异性与织构教育部重点实验室,辽宁沈阳110819

出　　处：《轻合金加工技术》2020年第12期58-67,共10页Light Alloy Fabrication Technology

基　　金：国家重点研发计划(2016YFB1200506-12).

摘　　要：对42 mm厚6082-T6铝合金FSW接头搅拌区中的"S"线特征进行了详细表征,并研究了不同"S"线特征对FSW接头弯曲性能和拉伸性能的影响。结果表明:搅拌区不同区域的"S"线特征存在明显差异,距接头表面5 mm范围内轴肩影响区的"S"线主要以氧化物条带形式分布,宽度为400μm^900μm。随着距表面距离的增加,轴针影响区的"S"线呈断续分布,氧化物条带变窄。轴肩影响区和轴针影响区不同的"S"线特征,对接头力学性能的影响也明显不同。位于接头上、下表层分层拉伸试样的伸长率分别为2.3%和1.8%,明显低于其他位置分层拉伸试样的伸长率(7.1%~8.3%)。表层分层拉伸试样的断裂路径沿着"S"线扩展,而其他分层拉伸试样则断裂于接头的软化区。接头侧弯试样和取自表层的分层弯曲试样在弯曲过程中均出现裂纹,并且裂纹起源于轴肩影响区的"S"线。从以上结果可见,轴肩影响区中以氧化物条带形式连续分布的"S"线是导致该区力学性能降低的根本原因。The characteristics of "S" line in the stirring zone of 42 mm-thick 6082-T6 aluminum alloy FSW joint were characterized in detail, and the effects of different "S" line characteristics on the bending and tensile properties of the joint were studied. The results show that the characteristics of "S" lines in different regions of the stirring zone are obviously different. The "S" lines in the shoulder-influenced zone within 5 mm from the joint surface are mainly distributed in the form of oxide strips with the width of 400 μm-900 μm. With the increase of the distance from the surface, the "S" line in the influence zone of the needle is discontinuous, and the oxide band becomes narrow. The influence of "S" line characteristics on the mechanical properties of the joint are also different. The elongation of the layered tensile specimens on the upper and lower surface layers of the joint is 2.3% and 1.8%, which is significantly lower than that of the layered tensile specimens at other locations(7.1%-8.3%). The fracture path of the layered tensile specimens extends along the "S" line, while the other layered tensile specimens fracture in the softening zone of the joint. Cracks appear in the bending process of the joint side bending specimens and the layered bending specimens from the surface layer, and the cracks originate from the "S" line in the influence zone of the shoulder. It can be seen from the above results that the continuous distribution of "S" lines in the form of oxide strips in the shoulder-influenced zone is the fundamental reason for the degrading of mechanical properties in the zone.

关 键 词：6082铝合金 厚板 搅拌摩擦焊 “S”线 力学性能 

分 类 号：TG[金属学及工艺]