5A06-O铝合金双轴肩搅拌摩擦焊接头微观组织和力学性能

Microstructure and Mechanical Properties of 5A06-O Aluminum Alloy Joints Prepared by Bobbin-tool Friction Stir Welding

对4mm厚5A06-O铝合金进行了双轴肩搅拌摩擦焊接试验,分析了接头组织演变与力学性能。结果表明:在参数合适的条件下,可获得无内部缺陷的5A06-O铝合金双轴肩搅拌摩擦焊接头。接头组织分为母材区、热力影响区、热影响区和焊核区。接头硬度曲线呈现出“N”型分布。接头的拉伸强度可达321 MPa(为母材的94%),伸长率可达14.38%(为母材的72%)。接头的断裂位置位于焊核,断裂形式属于韧性断裂,韧窝内粒子主要为Mg2Al3强化相和少量Mg2Si。

Bobbin tool friction stir welding experiments of 4mm thick 5A06-O aluminum alloy plates were carried out.The microstructure and mechanical properties of welded joints were analyzed.The results indicate that inner defect-free joints can be obtained under proper parameters.The microstructure of joint can be divided into four zones such as base material zone,thermo-mechanically affect zone,heat affected zone,and weld nugget zone.The hardness distribution of the joints is N-shaped.The joints exhibited a maximum tensile strength of 321 MPa(94%of the base material)and an elongation of as much as 14.38%(72%of the base material).All the joints in tensile test fracture in a ductile manner at the weld nugget zone.The particles in the fracture dimples are mainly Mg2Al3 and a small amount of Mg2Si.