*2.3. COMSOL Solution*

In this simulation, the temperature field and thermal stress field of the laser cladding material were simulated. A planar continuous heat source shown in Figure 4 was used to simulate the laser heat source; the laser heat source is directly loaded onto the cladding surface, while the laser defocus is adjusted by the heat source radius. The required physical fields module can be added in COMSOL according to the requirements.

The temperature field simulation needs to be calculated in "solid heat transfer" physical field, while the solid heat transfer and thermal stress field simulation physical fields need "solid mechanics" physical fields, so these two physical fields need to be loaded in the simulation.

The cladding layer model was established in advance. In order to prevent the uncladding part from affecting the part under cladding, the "activated" node of COMSOL

was used to simulate the laser cladding process during the numerical simulation calculation. Some parts of the field are deactivated before starting, while the deactivated part is multiplied by a small scaling factor to reduce the performance parameters of the material from the overall calculation. When the laser light source moves along the cladding path, the disused part is gradually activated and participates in the whole operation.
