Simulation Of The Microstructure Evolution During Laser Cladding Using Phase-field Method

Laser cladding is an additive manufacturing process. As a special machiningmethod, laser cladding has lots of advantages including small heat affected zone,excellent product performance, wide range of application and high efficiency. Lasercladding technology has the broad application prospect in the field of materialsurface modification and expensive parts repairing.Considering the combined effect of process parameters, this author build amacro-micro coupling calculation model combining macro temperature field modelwith phase-field model. The model is used to reproduce microstructure evolutionprocess during laser cladding and provides theoretical guidance for effective controlof microstructure formation of laser cladding process.First, macro process of laser cladding is simulated combining laser claddingcoating development model with the macro heat transfer model. The cladding layerdynamic change process is accurately reproduced and the temperature change rule isalso reflected.Secondly, the growth environment of laser cladding microstructure is obtainedthrough macro heat transfer calculation. Microstructure evolution of different moltenpool location is simulated using the phase field model based on free energy. At thebottom of melt pool, dendrite is long columnar crystal. At the upper part of melt pool,dendrite is asymmetric equiaxed dendrite.Thirdly, considering the influence of metal flow no macro temperature field andthe molten pool shape during powder preset laser cladding, microstructure evolutionprocess of binary alloy at different molten pool location is simulated. Simulationresults truly reflect the phenomenon of latent heat releasion, heat diffusion, solutediffusion, solute concentration and micro segregation.Finally, laser cladding experiment is carried on. Simulation results are in goodagreement with the experimental results, which can validate the model established inthis article.