水下搅拌摩擦焊接铝合金组织与性能研究
Microstructure and Properties of Submerged Friction Stir Welding Aluminium Alloy
丁凯
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作者单位：西安建筑科技大学
中文关键字：水下搅拌摩擦焊接；铝合金；显微组织；力学性能
英文关键字：submerged friction stir welding; aluminium alloy; microstructure; mechanical property
中文摘要：采用水下搅拌摩擦焊接技术(Submerged Friction Stir Welding，SFSW)对2024-T4铝合金板材进行了连接，研究了焊接接头的微观组织和力学性能。结果表明：水下搅拌摩擦焊接可以显著细化晶粒，焊核区的平均晶粒尺寸达到700 nm，但焊核区的析出相明显粗化。焊接接头的抗拉强度为母材抗拉强度的86.9%，焊核区和热机械影响区交界处成为接头的薄弱区。沉淀强化对接头性能起到主要作用，细晶强化作用较弱。
英文摘要：2024-T4 aluminium alloy plate was jointed by submerged friction stir welding (SFSW), and the microstructures as well as mechanical properties of the weld were measured experimentally. The results show that SFSW causes significant grain refinement with an average grain size of 700 nm but coarse precipitates in the nugget zone. The ultimate tensile strength of the weld is 86.9 percent of the base metal. The interface between the nugget zone and the thermo-mechanically affected zone is the weak zone of the SFSW weld. Precipitation strengthing is the main strengthing mechanism while the grain refinement strengthing is relatively weak.