| The laser powder deposition (LPD) process is an area of laser material processing that has received much attention in the past three decades. In this process, the laser beam as a heat source melts a substrate or previously deposited layer of material while the feedstock in the form of powder simultaneously enters the molten pool. The molten material solidifies just after the laser beam moves away from the molten pool. By moving the laser cladding head with respect to the workstation, a bead of material is deposited. Putting a number of beads side by side makes a layer of deposited material; and putting layers of material layer by layer can make a buildup. This process has different applications such as rapid manufacturing, surface modification, and repairing high value components. Researchers have attempted to modify and promote the LPD process through optimization of the process parameters, microstructural studies, simulation and control, and modeling the heat transfer and stress. The process developments, conversely, encompass the subjects related to: connecting microstructural evolutions back to the process parameters, improving the buildup quality, reducing the design-to-product time, developing the closed-loop feedback control system, integrating the general design rules with process specific capabilities, and lowering the machine costs.;In order to address the mentioned challenges in the LPD process, in this dissertation, a multi-disciplinary study of the LPD process is covered to describe: (a) thermo-kinetic modeling of the process, (b) thermo-structural modeling of the process, and (c) the vibration-assisted LPD process. In the thermo-kinetic modeling of the LPD process, the focus is placed on identifying the effect of the deposition pattern as one of the process parameters, the final properties, and the microstructural evolutions of the process. The thermo-structural modeling of the process addresses the effect of the deposition pattern on the residual stress formation in the material. The vibration-assisted LPD process introduces the application of in-process vibration on improving the microstructure of the material and reducing the porosity and defect level.;Keywords: laser power deposition, thermo-structural modeling, deposition pattern, vibration-assisted LPD process... |
