Hamed Attariani, Ph.D. (Advisor); Nathan W. Klingbeil, Ph.D. (Committee Member); Ahsan Mian, Ph.D. (Committee Member)
Master of Science in Mechanical Engineering (MSME)
One of the technological challenges in the widespread application of additive manufacturing is the formation of undesired material microstructure and defects. Specifically, in metal additive manufacturing, the microstructural formation of columnar grains in Ti-6Al-4V is common and results in anisotropic mechanical properties and a reduction in properties such as ductility and endurance limit. This work presents the application of hexagonal and circular arrays of synchronized lasers to alter the microstructure of Ti-6Al-4V in favor of equiaxed grains. An anisotropic heat transfer model obtains the temporal/spatial temperature distribution and constructs the solidification map for various process parameters, including laser power, laser scanning speed, and internal distance between lasers in the array. Some degree of laser overlap is recommended to maintain continuous melt pools. The results, particularly at higher power settings and lower scanning speeds, indicate the attainability of equiaxed grains, suggesting a degree of control in microstructure formation in additive manufacturing.
Department or Program
Department of Mechanical and Materials Engineering
Year Degree Awarded
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