Fig. 1. Models of laser fusion. (a) Finite element model; (b) physical model

Fig. 2. Cloud maps of temperature fields for laser fusion under different preheating temperatures. (a) 25 ℃; (b) 150 ℃; (c) 250 ℃; (d) 350 ℃

Fig. 3. Schematic of path position in longitudinal section

Fig. 4. Temperature changes along monitoring path in longitudinal section

Fig. 5. Temperature gradient changes along monitoring path in longitudinal section

Fig. 6. Schematic of monitoring path position on upper surface

Fig. 7. Temperature changes along monitoring path on upper surface

Fig. 8. Temperature gradients along monitoring path on upper surface

Fig. 9. Position diagram of monitoring points

Fig. 10. Temperature changes of monitoring points with different distances away from upper surface under different preheating temperatures. (a) 0.5 mm; (b) 1.5 mm; (c) 2.5 mm; (d) 4 mm

Fig. 11. Temperature changes at different depths under different preheating temperatures. (a) 25 ℃; (b) 150 ℃; (c) 250 ℃; (d) 350 ℃; (e) 550 ℃