常规FSW与双轴肩FSW对铝合金接头组织和性能的影响

对采用常规FSW和双轴肩FSW所得到焊接接头性能进行试验研究,测试了两种焊接得到的焊接接头的抗拉强度、屈服强度和断后伸长率,并对接头的微观组织和断口形貌进行了观察和分析.结果表明,双轴肩FSW接头横截面形成了一组由内向外扩张“洋葱环”状的椭圆环；常规FSW焊核区与热力影响区之间组织发生明显变化；硬度的最低处为双轴肩FSW前进侧热力影响区,最高处为双轴肩FSW接头上表面焊核区；常规搅拌摩擦焊接头的综合力学性能最好,双轴肩次之；断口形貌分析表明,接头断裂模式均为韧性断裂,且常规FSW断口韧窝尺寸比双轴肩FSW接头韧窝小而深,表现出更好的塑性.

Effect of welding ways on microstructure and mechanical properties of 6082 aluminum alloy

Friction-stir welding (FSW) of 6082 aluminum alloy was welded by conventional FSW and bobbin-tool FSW.Microstructure and mechanical performance of the as-prepared joints samples were examined.Some inside-out onion rings can be observed in the cross section of bobbin-tool FSW joints samples in microstructure analysis.Microstructure of nugget and TMAZ are obviously different,which shows the evolution of the microstructure.The results indicate that the general mechanical properties of samples prepared by conventional FSW are better than that by bobbin-tool FSW.Sample prepared by bobbin-tool FSW has a finer average grain size than that by conventional FSW.The cavities in the fracture appearance of bobbin-tool FSW joint sample are shallower and there are some smooth platform which are similar to the quasi-cleavage crack near these cavities.While the deeper cavities can be observed in the fracture appearance of conventional FSW joint sample.The lowest hardness point of bobbin-tool AA 6082 FSW joint sample is located in the TMAZ,and hardness in the upper WNZ zone is the highest.