Simulation study on thermal effect of ceramic materials rapidly and remotely heated by a flat-top CW laser

Compared with other heating methods, laser heating has outstanding advantages and application prospects in the field of high-power, large-area, remote and continuous heating of ceramic materials. However, the physical phenomena and mechanisms involved in the heating process are difficult to explain experimentally. This problem is solved by simulating the process of the heating experiment. In this study, a three-dimensional (3D) model of the laser heating experiment was built and the nonlinear transient finite element method was used to analyze the silicon nitride ceramic materials irradiated by a 1080 nm flat-top continuous wave (CW) fiber laser. Secondly. This work investigated the thermal effects on laser heating of silicon nitride ceramic material from the given laser parameters and geometrical parameters and then studied the thermal effects on laser heating of silicon nitride ceramic material under different laser parameters and geometrical parameters. The results show that when the laser heat flux 25 W/cm2, the laser radius is 15 cm, the surface emissivity is 0.75, and the thickness is 4 cm, the temperature of the silicon nitride ceramic material can reach up to 1102.3 °C after heating for 600 s, without exceeding its melting point and phase transformation, which reflects the excellent heat-resistant property of the material. The temperature variation inside the material mainly includes the zone of rapid temperature rise and the zone of slow temperature rise (saturation zone). The higher the laser power and the surface emissivity, the higher the temperature can reach; the smaller the thermal conductivity and the sample thickness, the higher the temperature can also reach. Understanding the heating rate of ceramic materials is useful in determining how they will respond to a specific incident laser and environmental conditions, which provides a basis for studying the irradiation time that the ceramic material can withstand for different parameters without damaging the material structure, the material mechanical properties and the transient temperature field distribution.