Fig. 1. Multi-physics field coupling of temperature, flow and phase transition fields for laser surface heat treatment^[10]

Fig. 2. Typical laser surface heat treatment technology

Fig. 3. Four heat affected zones on the laser hardened surface of grey cast iron^[15]

Fig. 4. Laser remelting to form a "W" type surface structure^[34]

Fig. 5. Schematic diagram of the experimental setup for laser surface alloying^[54]

Fig. 6. Schematic diagrams of the powder feeding systems for laser cladding^[11]. (a) Preset powder feeding system; (b) coaxial powder feeding system; (c) off-axis powder feeding system; (d) wire feeding system

Fig. 7. Schematic diagram of the laser impact blasting device^[79]

Fig. 8. Microstructures after laser impact blasting treatment^[85]. (a) 3 J-once; (b) 4.6 J-once; (c) 6 J-once; (d) 4.6 J-twice; (e) 4.6 J-three times; (f) schematic diagram of microstructure change mechanism

Fig. 9. Interfacial morphology between the coating and the substrate. (a)(c) Interfacial morphology between AlCoCrFeNi high-entropy alloy and the substrate^[87]; (b)(d) interfacial morphology between AlCoCrFeNi high-entropy alloy with TiC and the substrate^[87]; (e)(f) surface morphology of arc welded and laser fused Inconel 625 coatings after wear testing^[85]

Fig. 10. Corrosion behavior of FeCrAl alloy in a hot water environment^[95]. (a)‒(c) Without surface treatment; (d)‒(f) after laser surface remelting

Fig. 11. Inhibition of crack expansion by compressive residual stresses^[105]

Fig. 12. Future trends of laser surface heat treatment^[110-113]

Table 1. Advantages and disadvantages of laser surface heat treatment