A FEM model for simulating temperature field in coaxial laser cladding of TI6AL4V alloy using an inverse modeling approach

In this paper, a 3D thermal finite element (FE) model is built for the simulation of temperature field in the laser cladding of Ti6Al4V (TC4) alloy. Instead of directly acquiring the geometric parameters of cladding layer and heat source for a concrete FE simulation through the measured data in experiments, this model is able to achieve temperature distributions for laser cladding with varying combinations of process parameters by constructing an adaptive cladding layer and moving heat source model using an inverse modeling approach. First, correlation experiments of single-track laser cladding TC4 powder on TC4 substrate were carried out based on central composite design (CCD) with the cladding parameters, laser power (400-600 W), scanning speed (500-700 mm/min) and powder feed rate (30-60 rev/min). Then the relationships between process parameters and the geometries of cladding layer as well as the radius of spherical heat source are derived via regression analysis as an inverse manner. In addition, the spherical heat source is originally employed in the FE thermal simulation of coaxial laser cladding process. Detailed 3D transient thermal analyses have been performed with temperature-dependent material properties and the calibration of heat source is also provided. The proposed model is validated by the numerical and experimental results. It is found that it has potential to be applied in the thermal simulation of laser cladding with varying process parameters, considering the variation of the characteristic dimensions of deposition bead and the heat source.