Modeling of temperature distribution and clad geometry of the molten pool during laser cladding of TiAlSi alloys

Abstract

The temperature varying principal of the molten pool is crucial to coatings’ cross-section sizes during laser cladding process, which can influence the performance of the coatings. In this study, a modified three-dimensional (3D) transient finite element model was presented to simulate the temperature evolution and clad geometry of the molten pool of TiAlSi coatings. The difference of thermal properties in TiAlSi powders and TiAlSi alloys were distinguished to improve the precision of simulation results through theoretical calculation. The Gaussian body heat source model was established. A temperature selection judgment mechanism was utilized to compare the average temperature of the element and the melting point of the material to distinguish powder and alloy elements. An exponential distribution of energy attenuation along penetration direction was employed to simulate the laser beam deflected by the powder particles and the void among the particles to correct Gaussian heat source. The effect of different laser power and scan speeds on the cladding layer morphologies were investigated. The track depth and width calculated by simulation were analyzed by polynomial fitting curves. The results showed that the track depth and width were directly proportional to laser power, whereas inversely to scanning speed. Geometric dimensions of cladding layers at arbitrary laser power (600–1800 W) and scan speed (0.005–0.025 m/s) can be computed by polynomial fitting equation. Track depth was more impressed by scanning speed. The track width and longitudinal size of cross-section geometry from the simulation results and experiment measurement were matched to validate the presented model. The modified 3D transient finite element model is able to describe the geometry of single-track laser cladding.