Fig. 1. Schematic illustration of laser welding

Fig. 2. Surface morphology of welded joint with Ni foil. (a) 1400 W; (b) 1450 W; (c) 1500 W; (d) 1550 W

Fig. 3. Microstructure of weld obtained at 1450 W welding power. (a) Morphology of weld; (b) magnified zone 1;(c) magnified zone 2; (d) map scanning of Mg element; (e) map scanning of Al element; (f) map scanning of Ni element

Fig. 4. Microstructure of weld obtained at 1500 W welding power. (a) Morphology of weld; (b) map scanning of Ni element; (c) map scanning of Mg element; (d) map scanning of Al element

Fig. 5. XRD analysis for magnesium/aluminum alloys joint (1450 W)

Fig. 6. Detection locations in welded joint for hardness testing and EDS of each detection location. (a) Detection locations; (b) EDS of testing location 2; (c) EDS of testing location 4; (d) EDS of testing location 9; (e) EDS of testing location 10

Fig. 7. Thermodynamic properties of Mg-Al, Mg-Ni, and Ni-Al binary alloys. (a) Formation enthalpy; (b) Gibbs energy

Fig. 8. Tensile fracture morphology of welded joint sample. (a) Macro fracture morphology; (b) AZ31 magnesium alloy side; (c) 6061 aluminum alloy side

Fig. 9. Schematics of laser fusion welded magnesium/aluminum alloys interface forming after adding Ni foil. (a) Stage of heat conduction (1400 W); (b) partial Ni foil melting (1450 W); (c) Ni foil melting (1500 W)