Microstructure and mechanical properties of friction pull plug welding for 2219-T87 aluminum alloy with tungsten inert gas weld

The friction pull plug welding (FPPW) of the 2219-T87 tungsten inert gas (TIG) welded joint was investigated, and the microstructures, precipitate evolution, mechanical properties, and fracture morphologies of this joint were analyzed and discussed. In this study, defect-free joints were obtained using a rotational speed of 7000 r/min, an axial feeding displacement of 12 mm, and an axial force of 20–22 kN. The results indicated that within these welding parameters, metallurgical bonding between the plug and plate is achieved by the formation of recrystallized grains. The microstructural features of the FPPW joint can be divided into different regions, including the heat-affected zone (HAZ), thermomechanically affected zone (TMAZ), recrystallization zone (RZ), heat-affected zone in the TIG weld (TIG-HAZ), and the thermomechanically affected zone in the TIG weld (TIG-TMAZ). In the TIG-TMAZ, the grains were highly deformed and elongated due to the shear and the extrusion that produces the plug during the FPPW process. The main reason for the softening in the TMAZ is determined to be the dissolution of θ′ and coarsening of θ precipitate particles. In a tensile test, the FPPW joint welded with an axial force of 22 kN showed the highest ultimate tensile strength of 237 MPa. The locations of cracks and factures in the TIG-TMAZ were identified. The fracture morphology of the tensile sample showed good plasticity and toughness of the joints.

对2219 - T87钨极惰性气体（TIG）焊接接头的摩擦塞补焊（FPPW）进行了研究，并对该接头的微观组织、析出相演变、力学性能及断口形貌进行了分析与讨论。在本研究中，采用7000转/分钟的转速、12毫米的轴向送进位移以及20 - 22千牛的轴向力，获得了无缺陷的接头。结果表明，在这些焊接参数范围内，通过再结晶晶粒的形成，实现了塞棒与板材之间的冶金结合。FPPW接头的微观组织特征可划分为不同区域，包括热影响区（HAZ）、热机械影响区（TMAZ）、再结晶区（RZ）、TIG焊缝热影响区（TIG - HAZ）以及TIG焊缝热机械影响区（TIG - TMAZ）。在TIG - TMAZ中，由于FPPW过程中塞棒产生时的剪切和挤压作用，晶粒发生高度变形并拉长。确定TMAZ软化的主要原因是θ′相的溶解以及θ析出相粒子的粗化。在拉伸试验中，轴向力为22千牛焊接而成的FPPW接头表现出最高的极限抗拉强度，为237兆帕。确定了裂纹和断裂发生在TIG - TMAZ中的位置。拉伸试样的断口形貌表明接头具有良好的塑性和韧性。