Laser welding is performed on 3 mm thick dissimilar 6063/A356 aluminum alloys, and the welded joints are subjected to two different post-weld heat treatments: direct aging (DA) and solution aging (T6). The microstructure and mechanical properties of the welded joints are analyzed using optical microscopy, scanning electron microscopy, and transmission electron microscopy, combined with microhardness testing and tensile testing. The results indicate that under appropriate welding parameters, the weld exhibits excellent formation, and the tensile strength of the as-welded joint reaches 192.5 MPa, which is 73.7% of that of the 6063-T6 base metal. After DA treatment, the tensile strength of the welded joint increases to 233.8 MPa, representing a 21.5% enhancement compared to the as-welded joint. Transmission electron microscopy analysis further reveals that after DA treatment, a large number of acicular β" phases precipitate in the heat-affected zone on the 6063 aluminum alloy side. These nano-sized precipitates exhibit a good coherent or semi-coherent relationship with the Al matrix, effectively hindering dislocation slip and significantly enhancing the joint strength. After T6 treatment, the Si-rich eutectic network in the weld seam is fragmented and spheroidized, transforming into a spherical or polygonal morphology. Consequently, although the tensile strength of the joint decreases, its elongation is significantly improved compared to that of the as-welded and DA-treated joints.
| 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 |