Fig. 1. Schematic of micro-texture preparation by nanosecond laser

Fig. 2. Schematic of single-side resistance spot welding

Fig. 3. Schematic of tensile-shear testing on SUS304/GFRP joint by single-side resistance spot welding

Fig. 4. 3D morphologies of micro-textures with different widths on stainless surface. (a) Untreated; (b) 0.1 mm; (c) 0.2 mm; (d) 0.3 mm; (e) 0.4 mm; (f) 0.5 mm

Fig. 5. Contact angles of molten GFRPs on SUS304 surfaces with different micro-texture widths

Fig. 6. Macroscopic morphologies of typical stainless steel /GFRP joint. (a) Front surface; (b) back surface

Fig. 7. Optical morphologies of typical stainless steel/GFRP joints at interface under different micro-texture widths. (a) Untreated; (b) 0.1 mm; (c) 0.2 mm; (d) 0.3 mm; (e) 0.4 mm; (f) 0.5 mm

Fig. 8. SEM morphologies of interfaces of typical stainless steel/GFRP joints with different micro-texture widths. (a) 0.1 mm; (b) 0.2 mm; (c) 0.3 mm; (d) 0.4 mm; (e) 0.5 mm

Fig. 9. Elements distributions of interfaces of typical stainless steel/GFRP joints along different paths. (a) Line 1; (b) line 2; (c) line 3; (d) line 4

Fig. 10. Tensile-shear force values of stainless steel/GFRP joints with different micro-texture widths

Fig. 11. 3D fracture images of SUS304/GFRP joints

Fig. 12. Fracture morphologies of typical stainless steel/GFRP joints. (a1)‒(a3) Fracture at GFRP side without micro-texture; (b1)‒(b3) fracture at stainless steel side without micro-texture; (c1)‒(c3) fracture at stainless steel side with micro-texture; (d1)‒(d3) fracture at GFRP side with micro-texture

Fig. 13. Mechanism of single-side resistance spot welding of stainless steel/GFRP under micro-texture control. (a) Macroscopic heat conduction joining; (b) untreated; (c) micro-texture width is suitable; (d) micro-texture width is wide or narrow

Table 1. Chemical compositions of 304 stainless steel

Table 2. Process parameters of laser texturing platform

Table 3. Process parameters of single-side resistance spot welding