For the friction stir welding of 3 mm thick 6005A-T6 aluminum alloy in a lap joint configuration, this paper investigates the effects of varying pin lengths and lap positions on the performance of the welded joints. The results show that the internal quality of the lap joint is sound. When the length of the stirring needle is constant, the tensile load of the weld when the lap plate is on the back side is higher than that when the lap plate is on the forward side. However, the length of the stirring needle has a great influence on the metal flow state inside the butt joint. When the butt plate is located on the backward side, the hook defect is connected to the S line; when the butt plate is located on the forward side, the hook defect presents a hook shape along the welding core area and the boundary line of thermal influence; when the butt plate is located at a certain position and on the backward side, the hook defect is connected to the welding core area. The maximum breaking load of the weld is 28 592.9 N when the length of the stirring needle is 3 mm, and the minimum breaking load of the weld is 23 514.7 N when the length of the stirring needle is 5 mm.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |