Fig. 1. High power semiconductor laser cladding control system and robot

Fig. 2. Macrographs of cladding coatings. (a) M1 cladding coating; (b) M2 cladding coating

Fig. 3. Morphology of interface between cladding coatings and substrate. (a) Interface between M1 cladding coating and substrate; (b) magnification of Fig.3(a); (c) interface between M2 cladding coating and substrate; (d) magnification of Fig.3(c)

Fig. 4. Microstructures in the middle of cladding coatings. (a) M1 cladding coating; (b) magnification of Fig.4(a); (c) M2 cladding coating; (d) magnification of Fig.4(c)

Fig. 5. X-ray diffraction patterns of cladding coatings. (a) M1 cladding coating; (b) M2 cladding coating

Fig. 6. Chemical elements distribution of M1 cladding coating. (a) Line scanning diagram; (b) V element; (c) Cr element; (d) W element; (e) Fe element; (f) Nb element; (g) C element; (h) B element

Fig. 7. Chemical elements distribution of M2 cladding coating. (a) Line scanning diagram; (b) element distribution

Fig. 8. SEM images in the middle of cladding coatings. (a) M1 cladding coating; (b) magnification of rectangle area in Fig.8(a); (c) M2 cladding coating; (d) magnification of rectangle area in Fig.8(c)

Fig. 9. TEM images of M1 cladding coating. (a) bright-field image of coating; (b) dark-field TEM image and corresponding SADP pattern of austenite; (c) dark-field TEM image and corresponding SADP pattern of martensite; (d) magnification of rectangle are in Fig.9(a); (e) dark-field TEM image and corresponding SADP pattern of M₂₃C₆; (f) dark-field TEM image and corresponding SADP pattern of MC

Fig. 10. Phase diagrams of Fe-C-B^[17]: (a) Partial isothermal section at 1000 ℃; (b) partial isothermal section at 900 ℃; (c) partial isothermal section at 800 ℃; (d) partial isothermal section at 700 ℃

Fig. 11. Hardness of cladding coatings and switch rail

Fig. 12. Impact properties of cladding coatings

Fig. 13. SEM images of impact fracture of cladding coatings. (a) Radial region of impact fracture of M1 cladding coating; (b) magnification of rectangle are in Fig.13(a); (c) radial region of impact fracture of M2 cladding coating; (d) magnification area of rectangle are in Fig.13(c)

Fig. 14. Friction and wear test results of cladding coatings and switch rail. (a) Friction coefficient; (b) wear loss