Author Affiliations
1College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, Jiangsu , China2Xi’an Gangyan Special Alloy Co., Ltd., Xi’an 710000, Shaanxi , Chinashow less
Fig. 1. Schematics of laser welding. (a) Laser welding; (b) molten pool morphology
Fig. 2. Schematics of sampling position and size of specimen. (a) Sampling position; (b) size of tensile specimen
Fig. 3. Weld morphologies under different heat inputs. (a)(a1)(a2) Low heat input (90 J/mm); (b)(b1)(b2) medium heat input (150 J/mm); (c)(c1)(c2) high heat input (200 J/mm)
Fig. 4. Effect of heat input on molten pool dimension. (a) Schematic of typical molten pool; (b) corresponding dimensions under different heat inputs
Fig. 5. Microstructures under different heat inputs
Fig. 6. Schematics of microstructure growth conditions during molten pool solidification process. (a) Constitutional supercooling condition; (b) expansion stage of columnar grains; (c) formation stage of equiaxed grains; (d) weld grain distribution
Fig. 7. IPFs, PFs, and distribution histograms of grain sizes and misorientation angles under different heat inputs
Fig. 8. Sub-grain structures at WS bottom and secondary dendrites at centerline of WS under different heat inputs. (a)(d) Low heat input (90 J/mm); (b)(e) medium heat input (150 J/mm); (c)(f) high heat input (200 J/mm)
Fig. 9. Tensile test results of weld seam under different heat inputs. (a) Stress-strain curves; (b) tensile strength and elongation
Fig. 10. Fracture morphologies under different heat inputs. (a) Low heat input (90 J/mm); (b) medium heat input (150 J/mm); (c) high heat input (200 J/mm)
Element | Ni | Mn | Si | Al | Ti | C | Fe |
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Mass fraction /% | 36.040 | 0.350 | 0.180 | 0.047 | 0.066 | 0.023 | Bal. |
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Table 1. Chemical compositions of domestic Invar alloy
No. | Laser power P /(W) | Welding speed v /(m·min-1) | Heat input / (J·mm-1) |
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1 | 2250 | 1.5 | 90 | 2 | 3000 | 1.5 | 150 | 3 | 3000 | 1.2 | 200 |
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Table 2. Laser welding process parameters of domestic Invar alloy