焊接速度对Mg/Cu异种合金搅拌摩擦焊接接头成形的影响

目的研究不同焊接速度条件下镁铜异种合金搅拌摩擦焊接接头的成形规律。方法在保证其他焊接工艺相同的条件下,通过改变焊接速度,比较分析了焊接速度对接头的表面成形、横截面形貌特征、微观结构及力学性能的影响规律。结果随着焊接速度从118 mm/min减小至95 mm/min时,焊缝表面成形变得更光滑,飞边显著减少,内部孔洞缺陷消失,焊缝成形质量显著提高;但继续减小焊接速度至75 mm/min时,焊缝内部却再次出现孔洞缺陷。结论采用工艺参数为950 r/min的旋转速度、95 mm/min的焊接速度焊接时,焊缝成形质量最高;中心混合区主要由层片状铜合金、颗粒状镁合金和金属间化合物Mg2Cu组成;接头抗拉强度最大,达81.5 MPa。

Effects of Welding Speed on Forming of Friction Stir Welded Mg/Cu Dissimilar Metal Alloy Joints

The paper aims to study the formation rule of friction stir welded Mg/Cu dissimilar metal alloy joints produced at different welding speeds. Under the condition of keeping the same welding process, effects of welding speed on surface formation, cross section, microstructure and mechanical properties of the joints were compared and analyzed by changing welding speed. The results showed that, when the welding speed was decreased from 118 mm/min to 95 mm/min, the weld surface became smoother, the flash reduced significantly and the hole-defect in the weld disappeared, which significantly improved the joint quality. However, the hole-defect formed again in the weld when the welding speed was continuously reduced to 75 mm/min. Meanwhile, the quality of the weld made at rotation speed of 950 r/min and welding speed of 95 mm/min is the best. The middle mixed area is comprised of layered copper alloy, granular magnesium alloy and intermetallic compound of Mg2Cu. Also, the tensile strength of the joint is the highest, and which can reach 81.5 MPa.