2024-T4铝合金水下搅拌摩擦焊接研究

Submerged Friction Stir Welding of 2024-T4 Aluminum Alloy

摘要:

分别在空气和循环水冷条件下对2024-T4铝合金板进行搅拌摩擦焊接（friction stir welding，FSW），研究了水冷介质对FSW接头组织性能的影响。结果表明：循环水冷介质具有明显的瞬时快冷作用，水冷介质下FSW可以显著细化晶粒，并抑制焊核区析出相的生长，焊核区的平均晶粒尺寸达到700 nm，析出相尺寸达到30~200 nm。水冷介质减弱了FSW接头的热软化效应，改善了接头的组织和性能，使焊核区HV显微硬度值提高了234 MPa，接头抗拉强度提高了52.2 MPa，但试样延伸率有所下降

Abstract:

2024-T4 aluminum alloy plate was jointed by friction stir welding (FSW) under air and cooling water circulation separately, and the effect of the cooling water on the microstructure and mechanical properties of the FSW joint was investigated. The results show that the cooling water circulation medium has a significant instantaneous cooling effect. Cooling water causes remarkable grain refinement with an average grain size of 700 nm in the nugget zone. The growth of precipitates is restrained by cooling water, and the size of precipitates is 30~200 nm in the nugget zone. Cooling water decreases the thermal softening effect on the FSW joint, thus improving the microstructure and properties of the joint. HV microhardness and tensile strength of SFSW joint are increased by 234 MPa and 52.2 MPa, respectively, but the elongation is decreased a little