镁合金高转速搅拌摩擦焊工艺研究

目的 研究镁合金高转速搅拌摩擦焊工艺及其对组织与性能的影响规律。方法 采用光学显微镜观察以及拉伸性能测试等方法，探索了1.5 mm厚AZ31B镁合金高转速搅拌摩擦焊接工艺，对其接头组织与力学性能进行了测试分析。结果 采用6000 r/min转速时，随着焊速从600 mm/min降低至100 mm/min，焊接接头隧道型孔洞缺陷消失；采用600 mm/min焊速时，2000~4000 r/min转速范围内可获得无缺陷的接头。拉伸测试结果表明，6000 r/min-100 mm/min焊接工艺下接头的拉伸性能最优，抗拉强度为235.33 MPa，为母材强度的87.92%。结论 镁合金采用高转速搅拌摩擦工艺可获得无缺陷的焊接接头，且采用高转速匹配低焊速的工艺可使接头的拉伸性能得到提升。

High Speed Friction Stir Welding Process of Magnesium Alloy

The paper aims to study the high-speed friction stir welding process of magnesium alloy and its influence on microstructure and properties. The high-speed friction stir welding process of 1.5 mm thick AZ31B magnesium alloy was investigated by optical microscopy and tensile properties test. The joint microstructure and mechanical properties were tested and analyzed. As a result, when the rotational speed was 6000 r/min, along with the welding speed decreased from 600 mm/min to 100 mm/min, the defect of tunnel hole in the welded joint disappeared. When 600 mm/min of welding speed was adopted, the joints without defects can be obtained at 2000-4000 r/min. The tensile test results showed that the tensile properties of the joints were optimal at 6000 r/min-100 mm/min, and the tensile strength was 235.33 MPa, which was 87.92% of the strength of the base metal. Defect-free welded joint of magnesium alloy can be obtained by high-speed friction stir process. The high-speed combined with the low welding speed process can improve the tensile properties of the joint.