Numerical modelling and influence of silicon addition on the surface analyses of laser deposited coatings on Ti-6Al-4V alloy

Laser cladding is a material processing method which utilizes the high-power density available from defocused laser beam to melt both metal coatings and a part of the underlying substrate. A theoretical method based on a numerical simulation using experimental results is anticipated as a contribution to the study of laser metal deposition (LMD). The aim of this research is to simulate the temperature distribution at various points during the laser cladding process of Ti-6Al-4V alloy. A 3D model was developed using COMSOL Multiphysics to solve the governing equations of the occurring fluid flows and heat transfers. The model is based on the experimental work of laser deposited Al-Si-Sn coatings on Ti-6Al-4V alloy. The model was developed to obtain insights on the behaviour of laser melted pools subjected to various process parameters. Simulation with 3D model with different values of various significant processing parameters such as laser power, scanning speed and powder feed rate influences the geometry and dynamics of the melt pool, and cooling rates. The melt pool flow, thermal and solidification characteristics had profound effects on the microstructure of the coatings.