6063-T6铝合金双轴肩搅拌摩擦焊接头组织及力学性能分析

Analysis on microstructure and mechanical properties of 6063-T6 self-reacting friction stir welding

对4 mm厚6063-T6铝合金进行了双轴肩搅拌摩擦焊接试验.结果表明,双轴肩搅拌摩擦焊可以实现6063-T6铝合金的焊接,得到表面成形良好且内部无缺陷的接头.接头宏观形貌为哑铃状,其微观形貌分为焊核区、热力影响区、热影响区及母材区.在搅拌头转速为1 200 r/min,焊接速度为400～700 mm/min的工艺区间内,接头强度呈先升高后降低的趋势,最高可达181.64 MPa,为母材的68.5%,硬度分布呈W状分布,接头断裂位置位于前进侧热影响区,断裂方式为韧性断裂.

Self-reacting friction stir welding experiments for 4 mm thick 6063-T6 aluminum alloy were carried out in this study.The results indicated that good surface appearance and inner defect-free joints could be obtained.The joint macro morphologies were dumbbell shaped and the joint could be divided into four microstructure zones i.e.base material zone,heat affecting zone,thermal-mechanical affect zone and weld nugget zone.The hardness distribution of all the joints were W-shaped.When the rotation speed was 1 200 r/min and the welding speeds were 400~700 mm/min,the tensile strength of the joint first increased and then decreased.The tensile strength of the optimized joint was 181.64 MPa which equaled 68.5%of that of the base material.All the failed joints fractured in the heat-affected zone at the forward side with a ductile fracture mode.