In order to study the microscopic dendrite epitaxial growth and steering mechanism of the deposited layer during laser deposition,a two-dimensional melting and solidification model for laser deposition of IN718 was built based on the combination of Euler multiphase flow technique and cellular automata approach.The temperature field,flow field and the evolution of the microscopic solidification organization of the deposited layer were obtained,the thickness of the epitaxial growth zone of the dendrite in the deposited layer was compared between the simulations and the experiments,and the mechanism of the steering of the top dendrite was analyzed.The results show that the temperature field interacts with the flow field,and the model predicts the thickenss of the deposited layer with error of about 7.0%.The top and the middle of the deposition layer have different crystal weave orientations,and the growth direction of dendrites is more favorable to the direction of the local thermal gradient.At the top of the deposition layer,the direction of the local thermal gradient is close to horizontal direction,and the growth direction of the dendrites has a smaller deviation angle from the local thermal gradient,thus forming dendrite region parallel to the laser scanning direction.
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