Butt welding of AA6063 aluminium cylindrical shells was performed using the orbital friction stir welding (FSW) method. Tool rotation speed and orbital speed (i.e., traverse speed of rotating cylinder during welding) were considered as variable, and the strength and the mechanical properties including tensile strength, microhardness, mode I fracture energy and mode I crack growth behaviour of manufactured cylinders were investigated experimentally. A novel and subsized test specimen was designed and manufactured for fracture testing of specimens extracted from both base metal and weld zone region of cylinders. The initial precrack was introduced along (i) the tool penetration through the pipe thickness (i.e., T‐direction) and (ii) along the tool travelling direction (i.e., L‐direction). It was found that the crack growth resistance and fracture energy values of FSW samples are greater than the corresponding values of base aluminium material along both “L”‐ and “T”‐directions. Also, the fracture resistance value in T‐direction was higher than the L‐direction for the whole tested FSW samples with different welding speeds.

中文翻译：

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轨道摩擦搅拌焊制铝缸的力学性能和断裂性能

AA6063铝制圆柱壳的对接焊是使用轨道摩擦搅拌焊（FSW）方法进行的。将工具旋转速度和轨道速度（即焊接过程中旋转圆柱体的行进速度）视为变量，并研究了所制造圆柱体的强度和机械性能，包括拉伸强度，显微硬度，I型断裂能和I型裂纹扩展行为实验上。设计和制造了一种新型的，尺寸较小的试样，用于从钢瓶的母材和焊接区区域提取的试样的断裂测试。初始预裂纹的引入是（i）刀具穿过管道厚度（即T方向）的穿透深度和（ii）沿刀具行进方向（即L方向）的穿透力。结果发现，FSW样品的沿“ L”和“ T”方向的抗裂纹扩展性和断裂能值均大于基础铝材料的相应值。同样，对于具有不同焊接速度的整个测试FSW样品，T方向的抗断裂强度值高于L方向。