Product Code: JLA_18_3_245

Authors:
Y. Cao
J. Choi
Department of Mechanical and Aerospace Engineering, University of Missouri-Rolla, Rolla, Missouri 65409-1060

Laser cladding is an additive manufacturing process in which a laser generates a melt pool on the substrate material while a second material in a powder or wire form is injected into that melt pool. Among all laser manufacturing processes, laser cladding offers the most extensive variety of possibilities to alter a component at its surface. Despite immense potential and advancements, the process model of microstructure evolution and its coupling with macro parameters of the laser cladding process has not been fully developed. To address this issue, a process model of microstructure evolution has been studied by utilizing a phase-field method. The phase-field method has become a widely used computational tool for the modeling of microstructure evolution with the advantage of avoiding tracking the interface explicitly and satisfying interfacial boundary conditions. In present work, the numerical solutions of a phase-field model have been analyzed. The linking of macroscale process and microstructure evolution was examined by considering the relationship of macro- and microparameters. The effects of thermal noise and melt undercooling on the solidification microstructure have also been studied. The predicted results with different undercoolings were compared with the microsolvability theory and a good agreement was found. Different solidification morphologies of different locations in the melt pool are also investigated. It was found that it is not the mass transfer but the heat transfer in the melt pool that dominates the solidification process.