超声振动对6061-T4铝合金搅拌摩擦焊接头组织和性能的影响

Effect of ultrasonic vibration on microstructure and mechanical properties of friction stir welded joint of 6061-T4 aluminum alloy

利用自主研制的试验装置,通过工具头将超声振动能量施加在搅拌头前方的待焊工件上,研究了超声振动能量对减少焊接缺陷、改善搅拌摩擦焊接头组织和力学性能的影响.对6 mm厚度6061-T4铝合金板进行了超声振动强化搅拌摩擦焊工艺试验,并与相同工艺条件下的常规搅拌摩擦焊进行了对比.结果表明,超声振动能够减小焊速/转速比较大时的焊缝内部隧道型缺陷,增大材料对接混合区宽度和焊核区体积,细化焊核区和热力影响区微观组织,提高接头抗拉强度和焊核区显微硬度.

Utilizing self-designed experimental device to exert ultrasonic vibration on the workpiece in front of the stirring tool,the effect of ultrasonic vibration on reducing weld defects, improving the microstructure and mechanical properties of friction stir welded joint was investigated experimentally. A series of tests on ultrasonic-vibration-enhanced friction stir welding were conducted on 6 mm thick 6061-T4 aluminum alloy sheets. The experimental results were compared with those by conventional friction stir welding under the same welding conditions. The results show that ultrasonic vibration could reduce the tunnel defects caused by a high ratio of welding speed to rotation speed, enlarge the width of mixed zone and the volume of weld nugget, refine the grains in the weld nugget and thermo-mechanical affected zone,and improve the tensile strength of joints and the microhardness in the weld nugget.