搅拌针形状及旋转速度对搅拌摩擦焊搭接接头迁移界面的影响  

Migration Interface of Friction Stir Welding Overlap Joints with Different Tool Geometries and Rotation Speeds

作　　者：金玉花[1] 黄振有 李常锋[1] 温雨[1] 王希靖[1] 

机构地区：[1]兰州理工大学材料科学与工程学院,甘肃省有色金属新材料省部共建国家重点实验室,甘肃兰州730050

出　　处：《稀有金属》2016年第5期467-472,共6页Chinese Journal of Rare Metals

基　　金：甘肃省自然科学基金项目(1014RJZA002);甘肃省硕导基金项目(1201ZTC028);兰州市科技局项目(01-0065);兰州理工大学博士基金项目(01-0765)资助

摘　　要：采用圆台形搅拌针和倒圆台形搅拌针分别对2 mm厚的AZ61B镁合金材料进行了搅拌摩擦焊(FSW)搭接试验,研究了搅拌针形状及旋转速度对搭接接头迁移界面的影响。研究结果表明,倒圆台形搅拌针作用下的搭接接头焊核区出现明显的分层现象,而圆台形搅拌针作用下的搭接接头焊核区分层现象不明显,并且前者的接头界面迁移高度较后者的低。旋转速度对接头的焊核区形貌及界面迁移高度也有重要的影响:随着旋转速度的增大,焊核区尺寸也逐渐增大;当焊速为定值时,随着旋转速度的增加,界面迁移高度也随之增加,当旋转速度超过一定值时,即圆台形搅拌头的旋转速度大于1200 r·min^(-1)或倒圆台形搅拌头的旋转速度大于1100 r·min^(-1)时,界面迁移高度将保持恒定或减小。剪切拉伸性能测试结果表明,断裂均起源于迁移界面,然后沿着垂直于载荷方向断裂;界面迁移高度越低,接头抗剪强度越高;与圆台形搅拌针相比,倒圆台形搅拌针获得的接头最大抗剪强度提高了10%。Friction stir overlap welding tests for 2 mm thickness AZ61B magnesium alloy were investigated by conical pin tool and reverse conical pin tool, respectively. The effect of pin geometry and rotation speed on the migration interface of overlap joints was also analyzed. The results showed that stratifications appeared in the weld nugget zone under the action of reverse conical pin, while the stratification of weld nugget was not obvious under the action of conical pin, and the interface migration heights of former joints were lower than that of the latter joints. Furthermore, the rotational speeds could also highly influence the weld nugget zone morphologies and the migration interface heights： with the rotation speed increasing, weld nugget zone size increased; when the welding speed was constant, the interface migration height increased with the increase of the rotational speed ; when the rotational speed exceeded a certain value, i.e. , the rotational speed of reverse conical pin tool was more than 1200 r·min^-1 or the rotational speed of conical pin tool was more than 1100 r·min^-2, interface migration heights would remain constant or decreased. The tension shear mechanical test showed that the fractures originated from migration interfaces, and then propagated along the direction perpendicular to the load; the lower the height of the migration interface was, the higher the shear strength of the joints became; moreover, compared with overlap joint welded by the conical tool, the maximum shear strength of overlap joint welded by the reverse tool increased by 10%.

关 键 词：搅拌摩擦焊 搭接接头 搅拌针形状 界面迁移高度 抗剪强度 

分 类 号：TG453[金属学及工艺—焊接]