Temporal Analysis of Temperature Distribution at a Laser Spot in Selective Laser Thermoregulation Using a High-Speed Radiation Thermometer

To clarify the mechanical properties of new high heat-resistant materials, the Selective Laser Thermoregulation (SET) method, a method of accelerated heating tests using a high-power laser, is being developed. The SET method uses a galvano scanner to scan the surface of the area to be heated with a fiber laser, aiming to heat the sample while dynamically compensating the temperature distribution. However, the SET method has a problem: the sample's temperature distribution fluctuates spatially and temporally due to the movement of the irradiation point of the laser, which heats the target to a high temperature. In this study, a 400 W fiber laser was scanned back and forth over the sample at scan speeds of 5, 10, and 15 m/s, respectively, and the sample temperature distribution was measured using a high-speed radiation thermometer at 1000 fps. The temperature distribution of the sample was measured using a high-speed radiation thermometer at 1000 fps. The amount of temperature increase at the laser spot was evaluated by curve fitting. The temperature increases at the laser spot decreased to 95.0, 85.1, and 75.7 К when the scan speeds were increased to 5, 10, and 15 m/s, respectively. For all scan speeds, the temperature increase at the laser spot was smaller at locations where the sample temperature was higher. The local temperature increase at the laser spot was successfully suppressed to about 4.5% of the maximum temperature of the entire sample without the laser spot.