Fig. 1. Experimental setup of laser cladding. (a) Processing system; (b) processing head

Fig. 2. Cross-sectional morphologies of cladding layers under different scanning speeds. (a) 2 mm·s-1;(b) 3 mm·s-1; (c) 4 mm·s-1; (d) 5 mm·s-1; (e) 6 mm·s-1; (f) 7 mm·s-1; (g) 8 mm·s-1; (h) 9 mm·s-1

Fig. 3. Dilution rates of cladding layers under different scanning speeds

Fig. 4. Cross-sectional morphologies of cladding layers under different powder feeding rates. (a) 1.80 g·min-1;(b) 3.13 g·min-1; (c) 4.37 g·min-1; (d) 5.60 g·min-1; (e) 6.93 g·min-1; (f) 8.17 g·min-1; (g) 9.40 g·min-1

Fig. 5. Content of sulfur element distribution along depth direction of cladding layer under different scanning speeds

Fig. 6. Temperature coefficient of surface tension for different alloys

Fig. 7. Schematic of direction of Marangoni convection in laser cladding. (a) Outward flow; (b) inward flow

Fig. 8. Distributions of main elements along depth direction of cladding layer under different scanning speeds. (a) 4 mm·s-1; (b) 5 mm·s-1; (c) 6 mm·s-1

Fig. 9. Schematics of molten pool morphology and solidification front. (a) Molten pool with inward flow; (b) molten pool with outward flow

Fig. 10. Microstructures of cladding layer. (a) Molten pool with inward flow, cross-section; (b) molten pool with inward flow, top region; (c) molten pool with inward flow, bottom region; (d) molten pool with outward flow, cross-section; (e) molten pool with outward flow, top region; (f) molten pool with outward flow, bottom region

Table 1. Chemical compositions of substrate and cladding powder (mass fraction, %)