(西安建筑科技大学 冶金工程学院，西安 710055)
摘 要: 采用水下搅拌摩擦焊接技术(Submerged friction stir welding, SFSW)对2024-T4铝合金板材进行连接，研究搅拌头转速对SFSW接头焊接温度场、焊核区析出相形貌以及接头力学性能的影响。结果表明：循环水冷介质具有明显的瞬时快冷作用；随着搅拌头转速从600 r/min增大到1 180 r/min，SFSW接头焊接温度场峰值由271.0 ℃增大到310.8 ℃；焊核区析出相在热循环作用下析出并长大。析出相的数量逐渐增多，尺寸增大；SFSW接头焊核区显微硬度平均值由117.5HV降低至99.2HV、抗拉强度和伸长率分别由403.3 MPa和3.24%降低至334.5 MPa和1.44%。
关键字: 铝合金；水下搅拌摩擦焊接；转速；组织；性能
（College of Metallurgical Engineering, Xi’ an University of Architecture and Technology, Xi’ an 710055, China）
Abstract:2024-T4 aluminum alloy plate was jointed by submerged friction stir welding (SFSW). The effects of rotation speed on the welding temperature fields of SFS weld, precipitate morphology of the nugget zone and mechanical properties of SFS weld were investigated. The results show that the cooling water circulation medium has significant instantaneous cooling effect; the peak value of welding temperature fields increases from 271.0 ℃ to 310.8 ℃ with the rotation speed increases from 600 r/min to 1180 r/min. The precipitate phases of the nugget zone precipitate and grow under welding thermal cycle. The quantity and size of the precipitates gradually increase with the increase of the rotation speed. The average value of microhardness in the nugget zone of SFS weld decreases from 117.5HV to 99.2HV with the increase of the rotation speed, meanwhile, tensile strength and elongation of SFS weld decrease from 403.3 MPa and 3.24% to 334.5 MPa and 1.44%, respectively.
Key words: aluminum alloy; submerged friction stir welding; rotation speed; microstructure; properties
