摘要
用搅拌摩擦焊方法进行了异种LF6/LD31铝合金锁底接头焊接,研究了搅拌头轴肩下压量对焊缝成形的影响,分析了接头的截面形貌及力学性能。结果表明,搅拌头轴肩下压量对焊缝成形有重要的影响。组织分析表明,在焊缝横截面,LF6铝合金与LD31铝合金在焊核区被充分混合,并在焊核下部形成条带状的组织。焊核区由于受到搅拌头搅拌针的强烈搅拌作用,组织发生动态再结晶,由母材原始的板条状组织转变为细小的等轴再结晶组织。热力影响区晶粒随着向焊核靠近而逐渐变小且发生了明显的变形。当焊接工艺合适时,接头抗拉强度可达316MPa,达到母材强度,断裂部位多位于焊核与LD31铝合金的交界面。
Dissimilar materials, LD31 and LF6 aluminium alloy were joined by friction stir welding, and the effects of the position for the pin to be inserted on the weld appearance, microstructure and mechanical properties of joint were analyzed. The results show that a defect - free joint with good weld surface appearance can be obtained with suitable welding conditions for lock joint of the dissimilar materials. Optical microscopy reveals the stir zone presents particularly fine equiaxed grains, resulting in dynamic recrystallization. In the stir zone, the microstructure presents lamella alternately on the lower part. The maximum tensile strength of the joint was about 100% of that of the LF6 aluminium alloy base metal. The tensile failure happened at the boundary between the nugget and thermomechanically affected zone of the LD31 aluminium alloy, indicating that the weld has a higher joining strength.
出处
《南昌航空大学学报（自然科学版）》
CAS
2008年第1期15-19,26,共6页
Journal of Nanchang Hangkong University(Natural Sciences)
基金
江西省自然科学基金(0450090)
江西省科技厅重点工业发展项目(BC200201014)
关键词
搅拌摩擦焊
异种金属
组织
性能
friction stir welding
dissimilar metal joining
microstructure
property
