7N01-T4铝合金搅拌摩擦焊接头的形貌及力学性能

Morphology and mechanical properties of 7N01-T4 aluminum alloy friction stir welded joints

对15 mm厚7N01-T4铝合金采用3组焊接工艺参数进行搅拌摩擦焊。焊接速度均为200 mm/min,倾角θ均为0.5°,转速ω分别为300 r/min,350 r/min,400 r/min。所用搅拌头采用马氏体时效不锈钢制作,轴肩直径为37 mm,搅拌针为圆台形,针长14。8 mm,针体表面带有细牙螺纹和3个斜切平面。焊后进行外观检验、射线探伤、宏观断面检验、横向拉伸和弯曲试验。结果表明,3组参数所得焊缝外观良好,内部无孔洞、弱结合和S线等缺欠;焊接接头的抗拉强度在351 ～370 MPa之间,断后伸长率为11.9％ ～15.4％,拉伸试样均沿45°方向断裂,断口位于距离焊缝边缘约30 mm的区域;在弯曲180°的条件下,正弯和背弯试样均未产生裂纹。

7N01- T4 aluminum alloy plates of 15 mm in thickness were welded with 3 groups of friction stir welding parameters of welding speed at 200 mm/min and 0.5° tilt angle.Tool rotation speed is 300 rpm,350 rpm and 400 rpm,respectively.Tool was made of maraging stainless steel,and its shoulder diameter is 37 mm,the cone-like pin is 14.8 mm in length with fine thread and three oblique cutting plane on its surface.Visual inspection,RT,Macroscopic inspection,horizontal tensile and bending tests were carried out.Results show that all welds appearamces are good.There is no defect such as cavities,kiss bonding and 's' line in weld zone.Tensile strength of welded joints is from351 MPa to 370 MPa,the specific elongation is between 11.9%andl5.4%.Tensile sample fracture is along 45° direction,welded joints fracture occurs in base metal zone.There are no cracking in bending test at the bending of 180 degrees.Mechanical properties of 7N01- T4 aluminum alloy FSW joints meet the design requirements.