To obtain profiles with sound weld seams, the effects of extrusion parameters and heat treatment on microstructures and mechanical properties of the weld seam were revealed. It was found that the high extrusion speed increases the mechanical properties and welding quality of the welding area. The micro-voids formed in low temperature and low extrusion speed could hinder the grains from growing through the welding interface during heat treatment, which caused weak bonding of the weld seam. Lots of strengthening phases precipitated during aging treatment, which leads to the disappearance of the softened welding area and the improvement of tensile strength. However, the fine grains of welding area translated to coarse grains quickly during solution treatment, and the precipitated phases coarsened and the precipitation free zone (PFZ) widened when the aging time is excessive, above reasons result in the layered fracture of welding area and poor elongation. Tensile strength and elongation were improved simultaneously because of the fine grain boundary precipitates, narrow PFZ and fine homogeneous T₁ phases formed in under-aged (UA) treatment. The weld seam obtained by high extrusion speed shows a fine combination of ultimate tensile strength (UTS) and elongation after UA treatment.

为了获得具有良好焊缝的轮廓，揭示了挤压参数和热处理对焊缝的组织和力学性能的影响。发现高挤出速度提高了焊接区域的机械性能和焊接质量。在低温和低挤出速度下形成的微孔可能会阻止晶粒在热处理过程中通过焊接界面生长，从而导致焊缝的粘结性较弱。时效处理期间析出了许多强化相，这导致软化焊接区域的消失和抗拉强度的提高。但是，在固溶处理中，焊接区域的细颗粒会迅速转变为粗颗粒，时效时间过长时，析出相变粗，析出自由区（PFZ）变宽，上述原因导致焊接区域分层断裂，延伸率差。由于细晶界析出物，窄的PFZ和细小的均质T，同时提高了拉伸强度和伸长率未成年（UA）治疗形成_1个阶段。通过高挤出速度获得的焊缝在UA处理后表现出极限抗拉强度（UTS）和伸长率的良好组合。