Numerical simulation of thermal behavior and multicomponent mass transfer in direct laser deposition of Co-base alloy on steel

By Zhengtao Gan, G. Yu, Xiuli He, Shaoxia Li. 2017

412 citations recorded by the source corpus.

Abstract During direct laser deposition process, rapid melting–solidification and addition of multicomponent powder lead to complex transport phenomena in the melt pool. The thermal behavior and mass transport significantly affect the solidified microstructure and properties of fabricated layer. In this paper, an improved 3D numerical model is proposed to simulate the heat transfer, fluid flow, solidification and multicomponent mass transport in direct laser deposition of Co-base alloy on steel. The solidification characteristics, including temperature gradient (G), solidification growth rate (R) and cooing rate (G × R), can be obtained by transient thermal distribution to predict the morphology and scale of the solidification microstructure. Multicomponent transport equation based on a mixture-averaged approach is combined with other conservation equations. The calculated melt pool geometry and the composition profiles of iron (Fe), carbon (C), cobalt (Co) and chromium (Cr) are compared with the experimental results. The results show that in the initial stage of direct laser deposition, the rapidly mixture of substrate material and added material occur in the melt pool and conduct plays an important role in heat transfer due to the low Peclet number. As the melt pool is developed, the heat and mass transfer in the melt pool are dominated by strong Marangoni convection. An unmixed zone is observed near the bottom of melt pool where the convection is frictionally dissipated due to the presence of solidified dendrites. Since the G/R decreases and G × R increases from the bottom to the top of the solidified track, the morphology of the microstructure changes from planar front to columnar dendrites to equiaxed dendrites and the grain size decreases.

Subfields: Aerospace Engineering, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/6703ee53a326c4e104319b9a978d87c3cf6f9667

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Aerospace Engineering

1. T. Mukherjee
2. Gerald L. Knapp
3. H. Wei
4. T. DebRoy
5. Zhengtao Gan
6. Xiuli He
7. Shaoxia Li
8. G. Yu

In Mechanical Engineering

1. T. Mukherjee
2. T. DebRoy
3. H. Wei
4. Gerald L. Knapp
5. Zhengtao Gan
6. G. Yu
7. Xiuli He
8. Shaoxia Li

Citations in the corpus

• Grain size evolution under different cooling rate in laser additive manufacturing of superalloy (2019, methodology): “A numerical model involving heat transfer, fluid flow and mass transfer [14] had been developed to study the thermal and solidification behavior in direct laser deposition.”
• Modeling of thermal behavior and mass transport in multi-layer laser additive manufacturing of Ni-based alloy on cast iron (2017, methodology): “The detailed of conservation equations have been reported in our previous study [11,17].”
• Three-dimensional grain growth during multi-layer printing of a nickel-based alloy Inconel 718 (2019, background): “However, it is noted that the time taken to reach quasi-steady state will vary if the material and/or the processing parameters are changed [49].”