Author Affiliations
1Institute of Laser Engineering, Beijing University of Technology, Beijing 100124, China2Shanghai Institute of Optics and Fine Mechanics, China Academy of Science, Shanghai 201800, Chinashow less
Fig. 1. Schematic of welding device
Fig. 2. Size of tensile specimen
Fig. 3. Cross-sectional morphologies of welds. (a) Without niobium; (b) niobium with a mass fraction of 0.74%; (c) niobium with a mass fraction of 1.36%
Fig. 4. Microstructures of weld fusion zone. (a) Without niobium, fusion zone upper part; (b) niobium with a mass fraction of 0.74%, fusion zone upper part; (c) niobium with a mass fraction of 1.36%, fusion zone upper part; (d) without niobium, fusion zone bottom part; (e) niobium with a mass fraction of 0.74%, fusion zone bottom part; (f) niobium with a mass fraction of 1.36%, fusion
Fig. 5. Microstructures of weld center. (a) Without niobium, weld center upper part; (b) niobium with a mass fraction of 0.74%, weld center upper part; (c) niobium with a mass fraction of 1.36%, weld center upper part; (d) without niobium, weld center bottom part; (e) niobium with a mass fraction of 0.74%, weld center bottom part; (f) niobium with a mass fraction of 1.36%, weld center bottom part
Fig. 6. EBSD of microstructures and grain statistical results. (a) Without niobium, EBSD of fusion zone; (b) without niobium, EBSD of weld center; (c) niobium with a mass fraction of 0.74%, EBSD of fusion zone; (d) niobium with a mass fraction of 0.74%, EBSD of weld center; (e) without niobium, grain statistical result of fusion zone; (f) without niobium, grain statistical result of weld center; (g) niobium with a mass fraction of 0.74%, grain statistical result of fusion zone; (h) niobium with a mass f
Fig. 7. SEM backscattered photos of weld and EDS results of precipitated phases. (a)(b) Without niobium, fusion zone and its partial enlargement; (c) niobium with a mass fraction of 0.74%, fusion zone; (d)(e) niobium with a mass fraction of 1.36%, fusion zone and its partial enlargement; (f) EPMA area scan result of niobium; (g) EDS of Al2Mg3Zn3 precipitated phase; (h) EDS of MgZn2 precipitated phase; (i) EDS of Al-Nb precipitated phase
Fig. 8. Microhardness distribution of the top and bottom of the weld. (a) Top; (b) bottom
Fig. 9. Tensile strength of welded joints
Fig. 10. Macroscopic fracture position and microscopic fracture of tensile samples. (a) Macro fracture location; (b)(c) without niobium, microscopic fracture and its partial enlargement; (d)(e) niobium with a mass fraction of 0.74%, microscopic fracture and its partial enlargement; (f)(g) niobium with a mass fraction of 1.36%, microscopic fracture and its partial enlargement
Material | Mass fraction /% |
---|
Si | Fe | Cu | Mn | Mg | Cr | Zn | Ti | Zr | Al |
---|
A7204P-T4 | ≤0.3 | ≤0.35 | ≤0.2 | 0.2--0.7 | 1.0--2.0 | ≤0.3 | 4.0--5.0 | ≤0.2 | ≤0.25 | Bal. | ER5356 | 0.057 | 0.12 | 0.011 | <0.13 | 4.9 | 0.065 | 0.13 | 0.11 | Bal. | Bal. |
|
Table 1. Chemical composition of A7204P-T4 aluminum alloy and welding wire